View Full Version : Frequently Asked Questions (FAQ), Procedures and Resources

12-25-2006, 09:38 AM
This is modelled loosely on the Audi 100/A6 (C4 92-97) FAQ Digest page (see URL)

This is how it works: Basically we put a short articles or links to good posts as replies to this thread. You can upload pictures to the and attach them to your articles. Please follow the structure of the thread.

Also if you are about to type a comprehensive answer, type it in the FAQ thread list below this post or make a link to it in the FAQ thread. Always check to see if a thread has already been started in the FAQ, e.g. Cam Position Sensor (CPS), etc.

- Please refrain from asking questions, flaming people or posting a thank you in this collection. Post those on the main forum!

- Try to keep links linking to other sites to a minimum since they may not be there in the future. The same goes for using pictures from someone elses picture poster; those will be gone at some time as well.

To find things, either browse down the list or if you want something more directed, use your brower's "FIND IN PAGE" feature.

Thanks from the staff at STFA (Search the Forum Archives)(or, on a bad day, Search the Freakin' Archives!!!)<ul><li><a href="">Link to C4 A6/100 forum FAQ - which has lots of common C4 BTDTs</a></li></ul>

12-25-2006, 10:27 AM
Our 43 mm diameter fuel pumps have a finite life. They can fail as early as 80,000 miles or last as long as 250,000 miles. However, since they give little or no warning before they die (a bit longer cranking one or two days before they die), I personally advocate changing them every 100,000 miles (or less). They aren't that expensive ($120) if you do the work yourself. The procedure below works.

Best if you drive the car until the 15 L remaining fuel warning light comes on. That way you don't have to syphon fuel or have your arm in fuel to your elbow. To reduce the fuel pressure in the system, remove the gas cap, start the car and then remove the 20 amp No. 17 fuel pump fuse (panel at the drivers (LHD) end of the dash) and run the engine until it stops. Then remove the rear seat and disconnect the battery (have the radio code handy).

Ventilation!! Take a break if you feel dizzy. Better yet wear a vapour mask with carbon canisters.

See the URL for the procedure.<ul><li><a href=""></a</li></ul>

12-25-2006, 10:33 AM
The AAN will develop misses when there is spark plug, spark plug boot, coil, power output stagen (POS) or even MAF to Turbo hose problems. It can be nightmare to find the problem. Fortunately, there have been enough BTDTs that there are some logical procedures to help you figure out what the problem is an how to fix it.

See the posts below.

12-25-2006, 10:37 AM
This one should help you to sort things out. If the miss is just under boost, it is most often a coil but could be plugs or boots or even the MAF to Turbo hose. If the miss is all the time, it is likely one of the POS channels dieing.

Follow the procedure below and you should be able to sort it out.<ul><li><a href=""></a</li></ul>

12-25-2006, 10:43 AM
The fuel pump is powered by the general 12V power system. In stock form, the power goes from the battery (under the rear seat) to the ignition switch and then all the way back to the fuel pump (located in the trunk area, behind the battery). Since the wire gauge Audi used isn't the best, there are line losses of about 1 V. This may not seem like much but under load, e.g. Wide open throttle (WOT) and big boost, this lost 1 V is very important to the pump's ability to provide enough fuel. The solution is to relay the fuel pump to the battery (about 4 ft from the fuel pump). Sean D. and I developed a procedure to install such a relay. The result is the write-up in the URL below.<ul><li><a href=""></a</li></ul>

12-25-2006, 06:04 PM

12-25-2006, 06:07 PM
1.) Search The Forum Archives
2.) Search The ****in' Archives

<b>Alternative Definitions:</b>
1.) Stay The **** Away

12-25-2006, 06:29 PM
Life at 200k
By Paul Rivera - Quattro Quarterly, Fall 2001

For the Urq/S4 owners reading this, it will all be familiar. For those of you coveting ownership of this marvelous car, here is a little insight of what it's like to own one for an extended period.

Older Mercedes models, like the W123 chassis have a great reputation for durability and being able to run up to 1 million kilometers. Just ask the taxi drivers in Germany. In my opinion, modern Audis (1986 and newer) have that same capability. Our family Audi fleet is an example of this.

Having two S4s in our family, the '93 at 200K miles, and the '94 approaching 120K miles, has given us quite a knowledge base of just what one can expect "real-world" in owning these incredible cars.

Mike Rooney, of Ingolstadt West Audi Service in Chatsworth, California, is my resident S4 "Meister-wrench". I tapped him to assist in providing additional information for this story. He helps to maintain our fleet of 5 Audis in the family. Manfred Hageldorn, formerly of Rusnak Pasadena, moved back to Augsburg, Germany, and the other great Rusnak wrench was Johnny Reyes, recently hired by Audi Powertrain Development. Mike has taken their crown as the best Audi mechanic in this area. Manfred by the way, is now wrenching BMWs and has recently told me how superior he feels Audi engineering and production quality is to BMW (he is a little biased).

C4/S4s, built from 1992 to 1994, and C4/S6s, from 1995 to 1997, are identical in chassis design to the 100/A6 model sold between 1992 and 1997. C4 is the chassis identifier for a full size Audi chassis built in this era. Audi V8s and A8s are "D", and Audi 80/90 as well as A4 models are "B" chassis. We are now on the C5 chassis series (A6 1998 to?). Changes in tuning for the Urq/S4 (original) included not only power train, but springs, shocks, front sway bars, and rear sway bars fitted in some years. Also, there was a running production change with an additional firewall bracing upgrade installed starting in late 1992 and early 1993 C4 models. Interior details, like white face gauges, premium leather seating, and Bose Stereo systems were all standard in the USA specifications for this top of the line model. For the lucky few, S6 station wagons were imported between 1995 and 1997. Unfortunately, Audi USA never imported the V8 version of this car sold in Europe between 1992 and 1997. The V8 powered S6 Plus, sporting the S8 motor and 326 HP was the best and last of this model. Not to fret, as you read this, the new C5 based S6 Avant, with the S8-V8 and 340 HP, will be on the way to your local Audi dealer. Get one while you can!

The single most important section of this fine car is it's incredible power-train-five cylinders, 20 valves, dual overhead camshafts, fuel injection, and most of all, a sweet turbocharger. This motor, referred to as AAN, began life in the USA as a 3B motor in the 1991 Audi 200 20V turbo quattro. Audi engine boffins changed just about everything on the intake, injection and ignition side, as well as a totally different transmission, making this power-train the greatest and last example of the Audi 5 cylinder engine. As a side note, Acura-Honda, Volvo, and Fiat started making 5 Cyl. DOHC motors soon before Audi stopped. A real testimony to the vision of Dr. Pi?ch, the man behind the Audi 5 Cyl. concept.

You could call me a maintenance freak. I abhor any dirty or old lubricant, old anti-freeze, and especially old brake fluid. Timing belt changes become a religious discipline. Service schedules from the factory in my opinion are tuned to lower costs in the first tier of ownership, without regard to extending the life of the vehicle's power-train and brake system. How many times have you read "lifetime filled". Lifetime of who or what, the component in question? With my mentality of maintenance, I have received the reward for extremely long life of all of my cars. What I have found is that most S4 owners tend to be the same towards their cars.

There have been so many studies from MBA types that find the most optimum time to sell your car is below 50K miles. As the S4s in my family have been very reliable, I see no reason to sell the car at all. In fact we are expecting to keep the cars for some time to come.

Mike Rooney and I had a long lunch recently and reviewed not only the work that was done on our cars, but also things he has seen with all the other S4s he services.

When we listed all the areas of potential maintenance, it seemed like quite a scary list. Not all of these things have happened to either of our cars. However, if you look to buy a used one with high miles, or you too are set on a "keeper", you can expect some or all of these areas to need attention at some point in the car's life.

Mike says "Keeping clean lubricants and fluids is the cheapest form of preventative maintenance. I advise using high quality synthetics, like Castrol Syntech, Mobil 1, and Red Line. Change your synthetic engine oil at 5K intervals to be safe. Always use a German brand such as Mann, Mahle, Knecht, or authentic Audi Oil filter. Do not use Generic Orange, Yellow, White, or Blue filters (no names listed for law suit sake). The correct filters have 2 internal valves, a drain back valve and a by-pass valve. Most generic K-Mart/Pep Boys brands do not. If you use ordinary motor oils, please take care as I have seen even the famous Yellow brand form a gelatinous goop that can coat valve train components and end up clogging the pickup screen of the oil pump and cause oil starvation. I advise use of Castrol GTX, or Kendall Racing, with 3K oil change intervals. If you use a "Quick-Lube" place for oil changes, bring them the filter. Change the transmission and rear differential lubricant at 60K intervals at a minimum, preferably @ 30K using Audi/VW or Red Line synthetic gear lube. Brake fluid should only be Dot 4. Castrol, Mercedes, Audi/VW, or ATE. I do not advise use of domestic brands. Change at least annually and be sure to flush and bleed the clutch master and slave cylinders at the same time. Hydraulic Fluid for the steering/brake pump should be flushed and changed at the 30K service (at least), with the filter screen replaced if necessary. Use Pentosin or Audi/VW Synthetic only. Coolants should be phosphorous free, like the Audi/VW brand, Mercedes, or some other high quality brand. Change this annually as well. Most important major service is the 60K, when the timing belt, water pump, tensioner, and serpentine belt should be replaced in one shot. Saves a lot of labor cost as the water pump often does not last to the 120K service. Make sure you get your car on a hoist once in awhile so you can inspect the areas near the rear differential, drive shaft, and CV boots. Hard to see some problems when you are underneath the car.

It is rare that I have seen any S4 with enough miles to warrant rebuilding the bottom end. Valve trains seem to last well over 250K, with good fuel, clean lubricants and coolant, and a tuned motor extending the heads life. S4 motors well maintained could last up to 350K miles.

Below the approximate miles are listed in which you can expect parts to fail or need changing, and areas that need closer scrutiny.

Timing Belt and Serpentine Belt 60K.

Timing Belt Rollers and Tensioner, 60-120K

Power Steering/Brake Pump. Usually the seals will fail at 60-100K, and if you get an authentic ZF Seal kit, you can save the cost of buying a new pump.

Brake Accumulator. This is an expensive part and will last anywhere up 200K miles, yet may fail as early as 50K. A valve inside of the unit fails and renders the unit useless.

Steering rack. Usually it is seals as well that fail in this part. They can be re-sealed cheaper than replacing the unit. This will occur somewhere between 80-150K miles. Mike has resealed both of our cars once. High pressure accumulator and steering rack hoses are long life and start needing replacement around 120-150K. Several of these have been changed in either car.

Cooling System. Hoses. At 90-120K miles, consider changing all of them at one shot. Saves grief later. Aftermarket sources of German OEM quality are less than $175 for a complete hose kit. The little hose for the turbo coolant is hidden and should be replaced as well. Radiator. Neither of our cars have needed replacement yet. Unlike our V8 and 1991 200 where they failed at about 100K miles (plastic end tanks crack).

Plastic Heater Valve fails @100-200K miles.

Coolant Bottle and Cap will need replacing @ 50-120K miles.

Water Pump 60-120 K Miles. Clean coolant helps extend life.

Cooling Fan Motor. Have not changed yet in either car.

Aux cooling pumps. They seem to develop leaks more than just fail. Usually before 100k. Both have been changed on both cars.

Heater core. Not changed yet, again clean coolant extends life, 120-200K miles is typical for life.

Fuel Injection.

Hoses. The braided portion of these hoses can leak. Audi did have a recall, and I have had both of our S4 hoses changed, at 50-100K Miles.

Injectors. Still have the originals in both cars. Use of Techcron at each oil change service, good fuel, and frequent change of fuel filter @30K intervals) is needed for long injector

Fuel Pump. When it starts making lots of noise, time for a change. Usually 100-150k miles. '93 was changed at 170K, '94 has yet to go.

Turbo Charger. Clean oil, and letting the engine idle and the turbo cool down after a hard run helps as well. Intercooler hoses will fail at 50-200K depending whether the rubber rots or the excessive boost on a chipped car blows it out. MTM makes some reinforced hoses that are worth upgrading to, or change them all to Silicone "Samco" hoses.

Brake system Calipers Front. Stock Girling G60's are bulletproof with clean fluid. We changed both of our cars to the Mov'it Brembo/Porsche 993 TT calipers and matching rotors.

Brake Pads Front 10-25K Miles

Brake rotors front should be changed at 2-3 pad change intervals. Check minimum thickness specs and measure.

Brake pads rear Up to 100K on these.

Brake rotors rear. Maybe change @ 100K-150K if needed. Maybe resurface is ok too for one pad change. Again, check for the thickness specs and measure/replace accordingly.

Brake caliper rear. Here is an area of concern for our east coast and wet weather area owners. The hand brake cable can get rusted quite easily and lock up. Keep the entire handbrake mechanism and cable assembly clean and lubricated, and make sure the cable boots are intact and packed with some light grease. Neither of our S4s have been afflicted with this yet. My 1986 5KCSTQ had it bad as it was an east coast car.

CV joints. These usually last up to 300K Miles if the boots are intact, full of grease, and never exposed to dirt. Ours are original on both cars.

CV boots. These can need replacing somewhere around 80K-120K miles. When you change your shocks or suspension, change the boots at the same time. Inspect them regularly at each oil change.

Suspension. Front lower control arm bushings are the first to go, with sub-frame bushing needing replacement if the car has been driven hard or on really bad roads.

Steering damper goes out about the same time. 100-150K miles. Tie rods and ball joints can last up to 250K miles.

Front Strut Bearings take a beating and need replacing when you change your front shocks if not sooner.

Rear suspension is pretty reliable with the exception of rear camber links at 120-150k miles. Shocks. 80-120K miles on the front. Rears last longer, but change all four at once. Mike Rooney likes Bilstein. Konis are great too. Personal subjective preference. Both S4s have Bilstein, with different valving on each of the cars.

Springs start to show sag at around 200K miles.

Wheel Bearings. Not changed yet. Mikes says they can and change them when they are noisy.

Interior. Only the leather seat side bolster driver's side shows wear on either S4. All other interior pieces are in great shape. If you use floor mats, chances are your carpets are fine. Audi interior quality just cannot be beat and it only gets better in the newer cars.

Ignition. Spark Plug connectors. Here is a 60K item. Best to change them @60K service along with the plugs. Especially if the car is chipped. Seems to be a dealer only item, but Blaufernugen has them as well.

Spark Plugs. Use ONLY Bosch F5DPOR Platinum. Change at 30K intervals. Do not even think about a different plug.

Crankshaft Hall Sensor. If the car has hot start problems, this is usually the culprit, but has not failed yet on either car. Mike sees this rarely.

Oxygen Sensor. Change at 30K intervals if in doubt as by 60K they are usually not working well. Aftermarket Bosch with Audi connectors are a lot cheaper than the dealer. You can use the universal 3 wire, but the $ savings is only about $30-$40 and to me not worth the work in splicing in the wires.

Exhaust System. Audi spent the money on a high quality system, and we have not had to change it yet. Folks in the snow belt and wet areas may have different experiences. If you do change, use a stainless steel replacement like Audi original, or a quality stainless like a Stebro.

Catalytic Converters. They seem to have a long life. Have not needed changing on either car. Keeping the motor in tune has helped, I am sure.

Electrical systems. Audi really worked out the bugs and S4s are not plagued by any systemic flaws. Alternators are high output and rarely fail. Starter motors can last to 250K miles. Neither car has had either changed yet.

Instrument lighting is a small gripe. The exterior temperature gauge backlight fails eventually, and either means replacing the unit ($150) or re-soldering a replacement bulb. When you pull the instrument cluster to change a bulb, change all of the bulbs at one shot.

Seat heaters. Usually the driver's side will fail sometime up to 150K miles.

Sunroof switches @100-200K miles. Window motors and Seat motors rarelyfail.

Clutch. This depends on driving style. '93 changed at 150K, '94 changed by first owner under warranty at 32K miles. He was a gorilla.

Master and slave cylinder life is dependent on clean and fresh brake fluid. When changing the clutch, change all related parts such as pressure plate, pilot bearing, thrust bearing, and if necessary, the dual mass flywheel. Also, change the rear main seal, using only an original Audi factory part. Aftermarket seals seem not to be as good says Mike.

Air Conditioning. Sensors need replacing from time to time, and also the temperature control flap motor gives out at about 100K.

Interior fan motor usually needs replacing by 150-200K. Same on my V8, and my 1991 200. Related hoses may leak more with age then mileage.

Compressors seem to have a long life and rarely need replacing. No real trouble areas.

Vacuum hoses can be a problem. Especially the ones that run along the firewall that are covered by a plastic trim piece. The rubber rots and the clamps do a poor job. Change the hoses and the clamps when needed.

C4/S4s may be the last of the Audis that can be considered for ease of owner maintenance. As the new cars increase with technology, it becomes increasingly complicated to diagnose repair without the proper tools. There is a cool program for a PC laptop that will read all of the fault codes and reset the computers. You still need skill for the repair.

So here we are at 200k. What shape is the car in? Oil consumption is about one quart per 2K. A little smoke blows out the back when the car is cold, and we think it is time for the turbo to be rebuilt. The body is tight and handles well. Driver's seat needs reupholstering. Pearl White paint is in great shape. It really feels like the '93 can be driven for another 100Kmiles with just normal service. I am completely satisfied with this car (and the '94), and my son enjoys driving it every day. Practical hot rod if there ever was one. He can fit a 4-12" speaker cabinet and an amp head in the trunk, two guitars in the back seat and a band mate or two as well. I also have enjoyed watching the resale value stay strong. I hope to write again when this '93 hits 300K.

12-25-2006, 09:30 PM
Definition: In My High Horse Elitist Opinion

TM: Dave(UrS4Boy) 2006

12-25-2006, 09:58 PM
<b>Definition of FTW:</b>
1.) For The Win

<b>Definition of FTL:</b>
1.) For The Lose
2.) For The Loss

12-25-2006, 10:57 PM
If I Recall Correctly

12-26-2006, 01:09 AM
Another Useless Deutch Invention
Affectionately Used During Icestorms
Always Unusual Designs Incorperated.
Always Uncertain Door Ingress
Always Unanimous Doing It
Another Unlimited Driving Icon
Always Unorthodox Design Implementations
Awesomely Underrated Driving Icon
Always Under De Influence
Always Usurping Driver Income
Always Under Diagnostic Investigation
Always Underestimated Driving Instrument
Accelerates Under Demonic Influence
Automobile Underwater, Driver Insane
Attention: Unhappy Demons Irked
Already Umpteen Doorhandles Installed (or All ... Inoperative)
Appropriate Underground Destination Interface (only when "turbo" is rebadged "diesel")
Alienated Urban Drivers Intoxicated
Atrocious Useless Details Ignored
Approximately Universal Directional Indicator
Accelerator Under Dashboard Installation (think I'd better quit while I'm behind)<ul><li><a href="">slangish</a></li></ul>

12-26-2006, 02:23 AM
"I hope that I will soon forget the Audi Quattro. Until I do, I shall continue to worship that bitch goddess Success at the expense of friends, family, honesty and decency - anything to be in a position to have one. The Quattro is evil, an insidious witch in the guise of state-of-the-art engineering, a circe who commands your obedience every waking moment and a succubus who haunts every dream. She's the seductress who recreates That First Time all over again, who snips all your tethers to innocence and changes your life forever." - Four Wheeler Magazine, August 1982

12-26-2006, 03:35 AM
The Cam Position Sensor is used by the ECU (Engine Control Unit, i.e. the Motronic Computer) to figure out where the pistons are early in the starting cycle rather than waiting for the crank position sensor to come around. If the ECU does not get a cam position sensor signal, it will not fire the fuel pump relay. Once the engine is running, the ECU will use the crank sensor position sensor to keep track of things. If the cam sensor fails, a "2113" blink code will be thrown (into memory) and check engine light will come on. If it fails while running, you can keep driving but as soon as you turn the engine off, you are done. The engine will NOT re-fire until you fix the cam sensor. Location photo and diagrams in the URL links below.

12-26-2006, 03:36 AM
<ul><li><a href=""></a</li></ul>

12-26-2006, 03:39 AM
<ul><li><a href=""></a</li></ul>

12-26-2006, 04:04 AM
The ECU controls the fuel pump (FP) relay (J17)(PN 4D0 951 253) (located under the driver's side (LHD) knee bolster, right end of relay panel). The ECU will not engage the J17 until it has a signal from the cam position sensor (G40) during start-up and then the engine speed sensor (G28) during running. However, the FP relay does more than that.

Update: April 4/09: 4D0 951 253 which was the 208 relay is now superceded by 4D0 951 253B, the 372 relay. KATE's verbiage is:

"contact close relay for fuel pump
relay location/code no.: 6/372
to be used for code no.: 208"

Follow the URL for more info as to why the J17 is SO important.<ul><li><a href=""></a</li></ul>

12-26-2006, 04:12 AM
This should help if you are trying to track down a problem (electrical pun intended). You will still need a wiring diagram from the Bentley:

Pin-Out for the AAN ECU (or Engine Control Module (ECM)) T55 connector

The AAN ECU connector has 55 pin positions. The pins are arranged in three rows. The longest row has 19 pins, Pins 1 through 19. Pin 1 is nearest the metal release lever on the harness connector. The middle row is Pins 20 through 37, with Pin 20 nearest the metal release lever. The last row is Pins 38 through 55 with Pin 38 nearest the metal release lever. Not all pins are used.

The following are the Pins and their assignment. The information is taken from the Robert Bentley manual with comments based on VAG service manual 143 (VAG143) information and some experience.

The Letter/Number, e.g. N71, are for the devices that are either being controlled or are sending a signal to the ECU. The Letter/Letter code is the wire colour code. Not all pins are used - especially on the standard transmission cars.

Wire Colour Codes used in the pin-out list below:

BK = Black
BL = blue
BR = Brown
CL = Clear
G = green
GY = gray
LT G = Light green
OR = orange
R= red
V = Violet
W = white
Y = Yellow

W/V = white with a violet stripe
R/BK = red with a black stripe

Pin - Assignment - Device Code - wire colour - Comment (if any)

1/55 - Output to Power Output Stage - N122- G/W- for Coil No. 1 (N122 Pin 4/4)

2/55 - Output to Power Output Stage - N122 - V/BK - for Coil No. 2 (N122 Pin 3/4)

3/55 - Output to Fuel Pump Relay - J17 - BR/Y - ECU triggers the relay after it gets the G40 cam position sensor signal

4/55 - Idle Air Control Valve (aka Idle Stabilization Valve (ISV)) - N71 - W/Y the ISV is used to control the idle, e.g. when the air conditioning compressor comes on.

5/55 - Output (Fuel) Tank Breather valve N80 - W/R- Controls the evaporative emissions frequency valve - N80 - to cycle evaporated fuel vapours back in to the engine (NOTE: Bentley shows this as T55/3 on page X57 - presumably in error) VAG143 has it as N80.

6/55-Connection to A/C Control Head -E87- G/Y - Used to shut off A/C for up to 12 seconds when throttle is opened rapidly at speeds under 7 kph and shut off A/C for up to 3 seconds when in first gear and throttle position is at 65 degrees or more (full load) Ref: VAG143.

7/55-Mass Air Flow (MAF) Sensor - G70 - G/W - the MAF allows the ECU to know how much air (by mass) is heading to the cylinders so it can adjust the fuel, boost and timing to suit the conditions

8/55- Input from Hall Sender - G40 - GY/R - signal wire - Not lack of signal = Blink code 2113 and the engine will not start

9/55 - Barometric sensor - G16 - GY/BK - provides a signal to the ECU to help control boost at higher altitudes - between 1000 and 4000 meters - prevents the turbo from spinning over 155000 rpm.

10/55- Ground for Lambda (Oxygen) Sensor - G39-BR/R

11/55 -Input from Knock Sensor No. 1 - G61- G/G - for cylinders No. 1, 2 and 3

12/55- Power Supply (+5V) out to Hall sender - G40; Throttle Potentiomenter (G69) and Altitude Sensor (F96) - R/R -

13/55- Output to Data Link connector "L" for diagnostics - W/R

14/55-Ground for Fuel Injectors (N30-83)- BR/W - ground on intake manifold

15/55-Not Used

16/55 - Output control signal to Fuel Injector No. 5 - N83 - W/BL

17/55- Output control signal to Fuel Injector No. 2 - N31 - W/BR

18/55- Constant power supply to ECU J220 - R/R- from power terminal 30 (+12V) Fuse S26 (5A) - passenger footwell

19/55- Ground from the ECU for various ECU controlled devices - BR/R - to intake manifold

20/55 - Output to Power Output Stage - N127 - BK/Y - for Coil No. 4 (Note - some early versions of the Bentley have this as Coil No. 5 - but this is wrong, it is 4 - check it yourself) - VAG143 has it correct.(N127 connector Pin 4/4)

21/55 - Output to Power Output Stage - N127 - BK/W - for Coil No. 5 (Note - some early versions of the Bentley have this as Coil No. 4 - but this is wrong, it is 5 - check it yourself)- VAG143 has it correct. (N127 connector Pin 3/4)

22/55 - Data Link Connector - W/BL - linked to Check engine light (Malfunction indicator lamp) - also used in the blink code check.

23/55 - Output to Power Output Stage - N122- BK/GY signal for Cyl #3 Ignition coil (N122 connector Pin 1/4)

24/55- Power Ground for "actuators" other than injectors - Not found in Bentley, presume BR/R, ground to intake manifold

25/55- Mass Air Flow (MAF) Sensor (aka - hot-wire air volume meter) - G70 - G/V- Burn off signal from ECU - every time the engine is switched off, the hot wire is heated to 1000 deg C for one second to keep it clean

26/55- MAF - G70 - R/BK- "Reference voltage, earth (ground) in"

27/55- Switched Power to ECU from power (+12V) - BK/G - from Terminal 15 under the knee bolster - 15A circuit breaker, BK in BK/G out - S64

28/55- Heated Oxygen (O2) Sensor - G39- G/G- input from sensor

29/55-Input from Knock Sensor No. 2 - G66 - W/W- for cylinders No. 4 and 5

30/55- Ground for ECU and ECU sensors - G/BK

31/55- Fuel consumption signal for trip computer - BL/BK - Note: only used in N.America on 92 spec cars

32/55-Output toTrip Computer Boost Pressure Gauge - Y/BL - Note: only used in N.America on 92 spec cars

33/55 - Waste Gate Frequency Valve - N75 - Y/R - also know as the charge pressure control actuating valve - lets the ECU control the boost - by dumping excess boost through the waste gate

34/55 - Output control signal to Fuel Injector No. 3 - N32 - Y/BL

35/55 - Output control signal to Fuel Injector No. 4 - N33 - Y/G

36/55 - Output control signal to Fuel Injector No. 1 - N30 - W/V

37/55-Switched +12V for all 5 Fuel injectors (N30-N83) and MAF (G70)- BK/R - 15A - Circuit Breaker S72

38/55-T6ag Coding plug -Pin 1-GY/W

39/55-T6ag Coding plug- Pin 2- GY/Y

40/55-Input from Engine Speed Sensor - G28 - V/BK - Also connected to Ch.28 in the A/C head (you can read out RPM in the A/C head)

41/55-Signal from A/C control module -W/W - signal used by ECU to increase idle speed through ISV control when A/C compressor is activated (actually just maintains the idle speed when the extra load from A/C compressor is added to the system during idle)

42/55 -Gear selection input - Automatic only

43/55 - Not used

44/55 - Intake Air Temperature (IAT) Sensor - G42 - BR/BL - the ECU uses this signal to dial back timing (and power) to prevent pinging if the intake air temp is too high

45/55 - Engine Coolant Temperature Sensor - G62 - GY/BR - the one at the back of the head that the AAN ECU uses to figure out if the A/F should be enriched because the engine is cold.

46/55- Not used

47/55- Input from Crankshaft Position Sensor - G4 - V/V - used by the ECU to control ignition and fuel injector timing

48/55- Combined ground through ECU for G4 crankshaft position sensor and the G28 engine speed sensor - R wire from G4 and BL wire from G28

49/55-Input from Engine Speed sensor - G28 - GY/GY

50/55- Road Speed signal output (input?) to Instrument Cluster-G21-W/BL-signal also goes to Automatic Climate Control Head Channel 17 - which you can read out speed as well.

51/55- Not used for standard transmission cars - relates to shift point for automatic trans cars

52/55 - Idle Switch - F60 V/V- a microswitch inside the G69 throttle potentiometer that tells the ECU that the throttle is closed

53/55 - Throttle valve potentiometer - G69 - GY/GY the potentiometer on the throttle body that tells the ECU the degree to which the throttle body is open

54/55- Not used for standard transmission cars - relates to automatic trans cars

55/55- Output to Data Link connector "K" for diagnostics - G/R

12-26-2006, 04:17 AM
To clear engine fault codes in the AAN ECU, you can either disconnect the battery for 30 seconds (you will need the Radio code) or you can pull the ECU circuit breaker.

If you have accessed the ECU before, i.e. carpet is cut, etc. then you can clear the ECU codes by pulling the ECU circuit breaker (S64) for 30 seconds, in the red holder in the photo. (Photo courtesy of SJM Autotechnik (

To remove the ECU from the car, try this link:

If it doesn't work, you can find it via entering this in Google search window:

ECU removal (without the underscores_)

12-26-2006, 06:03 AM
<a href="">How to replace your sunroof rain gutter</a>

12-26-2006, 06:08 AM
<ul><li><a href="">Click Here</a></li></ul>

12-27-2006, 04:27 AM
In order to have speed limit set to 130 mph
you should bridge terminal 1 of coding plug to terminal 4 which results in terminal 38 of the ECU being connected to ground.

Coding plug can be found next to ECU in electronics box under the carpet in the
passengers footwell.

12-27-2006, 07:02 AM
<ul><li><a href=""></a</li></ul>

12-27-2006, 01:01 PM
Local to me but will ship to rest of Canada. Ask for Kris. Say "Dave F. sent me"<ul><li><a href=""></a</li></ul>

12-27-2006, 07:07 PM
<ul><li><a href=""></a</li></ul>

12-27-2006, 07:07 PM
<ul><li><a href=""></a</li></ul>

12-28-2006, 08:38 AM

12-28-2006, 04:33 PM

12-28-2006, 04:34 PM
AAN injectors
Run at 4.0 bar FPR in S4/S6
Bosch 0 280 150 951
Audi 034 906 031B

280 cc/ min @ 3.0 bar
315 cc/ min @ 3.8 bar
323 cc/ min @ 4.0 bar
361 cc/ min @ 5.0 bar

ADU (RS2) Injectors
Run at 3.8 bar FPR in RS2
Bosch 0 280 150 984
Audi 034 906 031F

360 cc/ min @ 3.0 bar
405 cc/ min @ 3.8 bar
416 cc/ min @ 4.0 bar
465 cc/ min @ 5.0 bar

12-28-2006, 04:37 PM
Courtesy of Jerry Scott.

The replacement of the standard manifold with the RS2 manifold is a somewhat difficult task, but is reasonably capable by anyone who has done mechanical auto work previously, and by someone who has a complete set of standard metric wrenches, metric sockets, metric allen wrenches, and a Mapp gas torch. You will also need a floor jack, a bench grinder, and a mechanic's trouble light. If you take your time, and are not frustrated by difficult to reach nut and bolt locations, you will find it a rewarding challenge. Three standard wrenches, (one 15 mm.
combination, and two 12 mm. combination) will need to be modified by grinding and bending, to accomplish the task. The wrenches were about $3.00 each.

1) Start by jacking up the car on the driver's side, (at the lift point under the front door), and remove the plastic bottom cover by turning with a screw driver, 8 quarter-turn screws. You may alternately want to run the front of the car up on ramp stands, instead of using a floor jack.

2) Drain the radiator of coolant from the plastic valve at the bottom of the radiator on the driver's side, into a container. This is necessary since you will need to disconnect two water lines from the turbo.
Alternately, you may try to catch the coolant in a bucket under the car, when you disconnect the turbo water lines, in a later step. The engine should be cool before starting this procedure.

3) Remove the plastic air filter cover by lifting and snapping it off from the inboard side. Remove the air filter box by flipping 4 wire buckles, then disconnect a wiring connector by removing the wire retainer and pulling the connector off. Loosen the airbox air intake hose at the hose clamp, then remove the airbox and filter from the car.

4) Remove the four nuts holding the waste gate to the manifold. Then remove the three nuts and bolts aft of the expansion bellows pipe, where it connects to the exhaust pipe. During reassembly, the gasket at this joint will need to be replaced, or if it is not damaged, can be reused.
Remove the air control line to the waste gate (one bolt). Put a piece of masking tape over the end of the bolt to keep from loosing the bolt and washer. This will now allow the waste gate assembly to be removed. Note that there is no gasket where the waste gate detaches from the manifold.
This is a metal to metal fit.

5) Remove the four nuts where the exhaust pipe connects to the hot sections of the turbo. The bottom of these 4 nuts is smaller (15 mm) than the other three 17 mm nuts, and is a little difficult to remove. It is the only one of the four with a washer. Use a 15 mm combination wrench at the box end. Heat and bend the wrench about 1.5 in. from the box end, with a 15 degree offset to clear the engine mount. Use an acetylene torch or Mapp gas torch (Sears), and a vise to heat and bend the wrench. A propane torch may not be hot enough. Buy an inexpensive forged steel wrench from Checker Auto for this purpose, (approximately:
$3.00). You may need to use a pry bar against the wrench to get the nut to break loose. Remove the four lines to the turbo, two at the top and two at the bottom. You will lose some antifreeze when you loosen the bottom lines, if you have not drained the radiator earlier. Tape the lower oil line with masking tape to keep debris out of this line while you are cleaning the gasket areas. There is a gasket on one line at the top and one line at the bottom of the turbo, that will need to be scraped clean and replaced, during reassembly. Do not use any gasket sealer when replacing these lines. One of the bottom lines will require removal of two bolts, with a 5 mm metric allen wrench.

6) Remove the four nuts holding the turbo to the manifold. The gasket at this joint should be replaced when reassembling. Note orientation of which side of the gasket is against the turbo.

7) Jack up the car under the front door at the lift point, on the passenger side; go under the car, and disconnect the exhaust pipe on the passenger side, just forward of the catalytic converter, by removing 3 nuts and bolts. If these are rusted, you may need to hacksaw these bolts to remove them, then replace them at your Audi dealer. Do not lose the steel ring gasket that will fall out. Lower the jack and jack up the driver's side of the car, then loosen the three bolts on the exhaust pipe on this side of the car. It is only necessary to loosen these bolts.

8) It is now possible to pull the exhaust pipe back to clear the turbo studs. It is helpful to hold the pipe back with a webbing strap and buckle. Attach it to the exhaust pipe and to the steering damper rod, then pull it tight.

9) Remove the large air input hose at the forward end of the turbo by loosening the hose clamp, and pulling the hose forward. There is also a small air hose at the forward end of the turbo that will need to be removed, by loosening a hose clamp. Disconnect the crankcase breather hose at the valve cover, by loosening a clamp and pulling it back.
Loosen the clamp for the turbo output hose, which is at the front and lower part of the turbo. This hose will not disconnect until you lift out the turbo assembly.

10) The turbo assembly can now be removed by first clearing the manifold studs, pulling it out of the rubber output hose, then by lifting it out.

11) Remove the 16 stud nuts and washers from the manifold with a 12 mm deep socket ratchet wrench. Remove the exhaust manifold and gasket.

12) The RS2 manifold requires that four studs be removed and replaced with shorter studs. A diagram supplied with the manifold shows which studs are to be removed. Make sure that you remove the correct studs.
The studs to be removed are: top row, # 6 counting from the front, and bottom row, # 4, 5, and 6 counting from the front. These studs can be removed with a Sears Craftsman 4458P stud remover. This tool grips the stud with a camed serrated wheel, which bites into the stud threads. The studs are not reusable after removal.

13) Now install the 4 shorter studs, with the shorter thread length going into the cylinder head, and the longer thread outward. Use two of the 12 mm nuts, jammed together on the stud to drive it into the head, with a 12 mm socket. Make sure that it is fully seated against the stud shoulder, then remove the two jammed nuts.

14) Place the RS2 manifold over the studs with a new gasket, having the shiny part of the gasket against the engine head. Now comes the difficult part. First put on the three bottom nuts on the short studs.
Do not reuse the copper washers on these three nuts. If you do, the thread locking part of the nut will not have enought engagement on the stud, and the nut may later work loose. Now put all of the other nuts on loosely, all with the copper washers. You will need to tighten the three bottom short studs first. These three studs will be difficult to tighten and will require tools to be modified, due to the small clearance around the nuts. Buy two 12 mm forged steel combination wrenches from Checker Auto, or your local auto store, for approximately $3.00 each.

15) For studs # 4 and 5, use an open end 12 mm combination wrench that has had the open end ground down with a bench grinder, to a .855 in.
outside width, then thickness of the open end ground down to .180 in., and the handle bent at approximately 10 deg. offset, 1.75 in. from the end of the open end. The bending can be accomplished again with an acetylene torch or a Sears Mapp gas bottle torch, and a vise. You will need to custom grind the wrench and try it until it fits over the two nuts.

16) For stud # 6 bottom row, (the most difficult to tighten), you will need to grind another 12 mm combination wrench, to remove some of the outer metal around the outside of the box end. Grind it down as far as you can go without cutting through the box ring, (approximately .650 in.
diameter). Now grind down the thickness of the box ring to about .225 in.. Put the box end in a vise, heat and bend the handle at 90 deg., about 1.5 in. from the end of the box end. Keep trying the wrench on the nut by looking through the hole in the manifold casting, and by making grinding adjustments as necessary, until it fits over the nut.

17) First, use the modified open end wrench to tighten # 4, then # 5, bottom row. Next tighten # 6, bottom row, by using the modified box wrench with a large square shanked screw driver, then twisted the wrench in the open end, like a t-handle. Tighten the top #6 nut with an open end 12 mm wrench, and the remaining nuts with a 12 mm deep socket ratchet wrench.

18) The remainder of the reassembly is the reverse of the disassembly.
Don't forget to add coolant before starting the engine. Audi requires a phosphate free, aluminum safe coolant, such as Autobahn sold by Audi, ($14.00/gal.), or Prestone Extended Life 5/100, ($7.00/gal.). The new manifold may smoke for a while after starting the engine, until the machining oils are burned off.

12-28-2006, 04:38 PM
Courtesy of Todd Kramer:

Helpful Hints:

1. Penetrating oil on all nuts to be removed. Problem areas: Accordian Pipe, Exhaust to turbo, turbo to manifold bolts. I have sheared numerous turbo studs off; this will incorporate a four day turn around with your local machine shop to tap them out. Do it the night before as you ponder your task...

2. Consumables:
a. ALL gaskets need to be replaced; they are not cheap. I used ECS tuning because they could get them to me quick and were competive with most shops (Accordian pipe gaskets, exhaust to turbo, turbo to manifold, manifold to head, oil lines (top, bottom, and block ... I bought material from Checkers and cut my own))
b. Nuts and bolts: the only hardware you can re-use (Bentley's Rule) are the header and turbo studs and the exhaust manifold washers. The manifold bolts are a $2.50 (each) dealer only item (these are a non-negotiable replacement item ... they are also used to attach the accordian pipe. The only I reused my best manifold bolts with the accordian pipe, but used new for the remainder. The turbo to manifold bolts are $11.00 (ea) dealer only item .. I re-used mine and have no leaks (14 months)
c. PENTOSIN antifreeze ... you will lose almost all of your coolant .. just drain it all ... and beware the lower coolant hose on the bottom of the turbo .. the head hold about a liter of coolant that will end up on the floor of your garage...position your basin accordingly.

3. Removing the turbo: Disconnect the lower oil line at the block. This makes the re-installation a breeze. Trying to attach the lower oil return line from underneath the car is a royal bitch. I also pulled the wastegate before pulling the turbo ... made access to the manifold/turbo bolts much easier. Be careful, I have sheared a WG stud or two in my times. (See Penetrating oil comment)

4. Cut the studs like on the link ... before you do this, thread your old manifold stud bolts on, with flat face out, this is a great way to make sure you chase the threads as you back them off. I cut #4,5,6 on the top and bottom ... my last intall was an IA RS2 manifold, so it had some castings that needed to be ground to ease installation.

5. If you have my 12mm wrenches (send address), they make the lower nuts less of a PITA to install, and the box end will allow you to tighten them as best as can be done. Yeah, they are short and will required a million repetions ... but they are much quicker than a standard wrench or socket. I would also suggest in investing in a 12mm gear wrench from Sears. The trick to tightening all the bolts is to put the manifold on the studs, finger tighten the corner studs to hold it in place, then install the rest of the bolts. Tighten all bolts to a 1/3 of the total length of the stud ... three iterations. With the manifold against the head, some of the heads of the bolts will bind such that you cannot get a wrench on them ... it will be painfully obvious if you tighten one too much...

6. Once the manifold is on, get the bolts as tight as a six point box end will let you ... the bolts are a copper alloy and will round very easily ... so don't get greedy. Some bolts are easier to get to from underneath the car.

7. Re-install the turbo, remember to fill the top oil hole with oil before you connect the oil line. I used a syringe and spun the compressor wheel to fill the housing with oil...keeps from dryspinning the turbine shaft. I used teflon paste on the water lines ... cheap insurance agains future leaks. I also used permatex non-hardening gasket compound to help seal the oil lines

8. Re-install the Wastegate

9. Install the downpipe loosely so you can, simultaneously, re-attached the accordian pipe. This can be difficult... When tightening the exhaust to the turbo, cross-tighten the nuts so you ensure a good seal .. top right, bottom left, top left, bottom right x 2 ... sequentially tighten/torque the bolts (70% torque, 100% torque) ... this helps not deform the gasket as you create the seal.

10. Once everything is back together, re-fill the coolant, fire her up and check for:
a. Oil Line leaks, top and bottom (gasket compound)
b. Coolant leaks, top and bottom (teflon paste)
c. Listen for exhaust leaks (clicks or puffing sounds); I used a 2-foot piece of hose to listen to the top and bottom of each cylinder and at the turbo connections and exhaust connections.. kinda like a stethascope (sp?), make the puffing very obvious ... if you hear something, tighten that spot and re-check.

11. After a tank of gas, re-do step 10 to make sure everything survived the heat-cycles of day to day driving.

12-28-2006, 04:42 PM
qty part number part description

1 034 253 031A RS2 Exhaust Manifold
5 034 906 031F "RS2 Injectors, Bosch P/N 0 280 150 984"
1 034 133 471N "RS2 MAF, Bosch P/N 0 280 213 017"
1 034 145 702B RS2 Turbo
1 034 129 589A Gasket (Manifold&gt;Head)
1 035 129 589D Gasket (Manifold&gt;Turbo)
1 447 253 115 Gasket (Manifold&gt;Downpipe)
2 857 253 115 Gasket (Downpipe&gt;Wastegate)
2 N 012 226 5 Washer (Turbo&gt;Oil Inlet Line)
1 035 145 773D Gasket (Turbo&gt;Oil Inlet Line)
2 N 012 226 5 Washer (Turbo&gt;Oil Return Line)
1 035 145 757D Gasket (Turbo&gt;Oil Return Line)
2 N 013 812 8 Seal (Turbo&gt;Water Feed Line)
1 N 013 814 9 Seal (Turbo&gt;Water Return Line)
1 N 013 814 9 Seal (Wastegate&gt;Pressure Line)
16 N 902 002 01 Nut (Manifold&gt;Head)
16 N 900 955 01 Washer (Manifold&gt;Head)
3 N 901 889 02 Stud M8x35 (EM&gt;Head) - Cut down to 22 mm
13 N 901 889 02 Stud M8x35 (EM&gt;Head) - Cut down to 27 mm
4 046 145 749 Nut M10 (EM&gt;Turbo)
4 N 902 002 01 Nut AM8 (EM&gt;Wastegate)
3 N 010 244 16 Bolt M8x30 (Flex Exh Pipe&gt;Downpipe)
3 N 900 850 01 Nut M8 (Flex Exh Pipe&gt;Downpipe)
3 N 902 002 01 Nut AM8 (Wastegate&gt;Flex Exh Pipe)
3 N 903 690 01 Nut M10 (Turbo&gt;Downpipe)
1 N 900 730 01 Nut M10 (Turbo&gt;Downpipe) - low clearance nut
1 N 011 560 8 Washer 10.5x18x1.6 (turbo&gt;downpipe)
2 N 023 002 8 Nut AM6 (Turbo&gt;Oil Inlet Line)
1 035 145 757C Gasket (Oil return line&gt;block)
6 N 010 353 3 Bolt M8x42 (downpipe&gt;cat)
6 N 900 850 01 Bolt M8 (downpipe to cats)
2 N 014 703 5 Bolt M6x18 (turbo&gt;return oil line)
2 N 014 703 5 Bolt M6x18 oil supply line to oil cooler

12-30-2006, 08:14 AM
<center><img src=""></center><p>
Also from the VAG Self Study guide 111

Pertinent N75 PN's are:

034 906 283 J = stock 3B (in 200 20v and S2)
034 906 283 H = stock AAN (UrS4 and UrS6)
034 906 283 K = S2 ABY and RS2 ADU<ul><li><a href="">Link to European Car N75 article on Skollie's server</a></li></ul>

12-30-2006, 08:16 AM
Note: These are the pertinent UrS car N75 PNs:

034 906 283 J = stock 3B (in 200 20v and S2)
034 906 283 H = stock AAN (UrS4 and UrS6)
034 906 283 K = S2 ABY and RS2 ADU<ul><li><a href="">Link to Skollie's posting of a European Car mag N75 article</a></li></ul>

Tornado //S6
12-30-2006, 09:34 AM
<ul><li><a href="">FAP</a></li></ul>

12-30-2006, 01:05 PM

12-30-2006, 10:36 PM
<ul><li><a href=""></a</li></ul>

12-31-2006, 07:01 AM
<ul><li><a href="">Worldimpex site</a></li></ul>

12-31-2006, 10:50 AM
I recently had one bulb burn out and decided to replace all four. This is an easy 15 minute job.

There are 4 bulbs, two 2 Watt and two 0.9 Watt.

The replacement bulbs are 893 919 040A for the 2W (green) and 4A0 919 040C for 0.9W (orange, which are really 1.1W).

1. remove the wood trim surrounding the HVAC, the easiest way is to open the ashtray and use your fingers to pull the trim out.

2. remove 2 hex screws holding HVAC in place.

3. pull out HVAC and you will see bulbs which are inserted from behind.

4. use a small flat blade screwdriver and turn each each bulb 90 degrees counter-clockwise.

5. Tilt the HVAC back and the bulbs will fall out.

6. The outer bulbs are the 2W ones and the inner are the 1.1W ones.

7. Re-install in reverse.

01-01-2007, 08:23 AM
<ul><li><a href=""></a</li></ul>

01-01-2007, 08:24 AM
<ul><li><a href=""></a</li></ul>

01-01-2007, 08:26 AM
<ul><li><a href=""></a</li></ul>

01-01-2007, 08:32 AM
<ul><li><a href="">Switch to the English page once you have seen their opening page</a></li></ul>

01-01-2007, 11:56 AM

01-01-2007, 12:23 PM
<ul><li><a href=";products_id=32">;products_id=32</a</li></ul>

01-01-2007, 02:17 PM
<ul><li><a href=""></a</li></ul>

01-01-2007, 09:44 PM
<ul><li><a href="">Click here and then on the their "S4/S6 5 cylinder 92-97" link.</a></li></ul>

01-04-2007, 07:28 PM
Excellent guide to replacing the ps pump by UrScubed.<ul><li><a href=""></a</li></ul>

01-06-2007, 03:05 PM
using the VAG 1552 or VAG com,

go to address word 08, function 07

enter 00051

Now the recirc button can be independently controlled from the A/C.

01-08-2007, 03:50 PM
Favorite Local Auto Parts Store

01-10-2007, 04:32 AM
<ul><li><a href="">Link to writeup</a></li></ul>

01-10-2007, 04:37 AM
<ul><li><a href="">Link</a></li></ul>

01-11-2007, 06:40 PM
From my Audifans post in Sept 2006:

- remove rear wheels

- remove exhaust at double clamps, support exhaust, remove hangers
and pull out exhaust

- remove plastic tray under gas tank

- remove bolts attaching trapezoidal arm to subframe, this allows
clearance between the inner CV joints and the axle flanges

- remove cover plate on left side of axle

- remove left handbrake cable bracket to diff

- unbolt right handbrake cable bracket from diff (one of the bolts
is obstructed, I used vice-grips)

- remove handbrake cable brackets holding to body (near driveshaft)

- remove triple square bolts from inner CV joints to the axle

- remove driveshaft CV joint to input flange bolts

- remove single nut holding the rear diff mount to the subframe

- remove muffler support cross member

- remove diff front cross member and support diff

- lower front of diff down slightly

- remove diff cross member from diff bracket

- remove diff bracket from front of diff and slide bracket over
input flange

- lower the front down farther and when at about a 30 degree angle,
lift the rear up allowing the rear mount bolt to clear the subframe

- lower diff to floor and remove

- remove rear mount bracket and install on new diff

As they say, installation is the reverse of removal, a few tips.

It's easier to lift the diff into position manually without a jack, although
its pretty heavy (~100 lbs). It took me a while to figure this out after
several fruitless attempts to use a floor jack that I have outfitted with a
12x12 square piece of 1 inch plywood bolted to the saddle. I did this by
lying on the garage floor and angled the rear up at the same 30 degrees and
guided the rear mount bolt into the upper hole on the subframe. Once it's in
there, you can jack up the front and install all the brackets and cross
member. Be careful to makes sure the handbrake cables don't get caught.

If you have the car on a lift, I'd suggest two people lift the diff and have a
transmission jack handy to support the front once the rear mount bolt is
engaged in the subframe.

01-13-2007, 03:37 AM
<ul><li><a href="">1st post- Nav+ crammed into C4 console</a></li></ul>

01-13-2007, 03:38 AM
<ul><li><a href="">Trim fab link</a></li></ul>

01-13-2007, 03:39 AM
<ul><li><a href="">Project update</a></li></ul>

01-13-2007, 05:14 AM
<ul><li><a href="">Double-DIN writeup</a></li></ul>

Ben Swann
01-13-2007, 01:30 PM
GTQuattro has several Do It Yourself Performance Kits now available for the earlier Quattro's. New kits continue to be added to provide easy and inexpensive modifications by providing instructions and components in a "DIY" Do It Yourself Kit.<ul><li><a href="">Do It Yourself Performance Kits by GTQuattro</a></li></ul>

01-28-2007, 01:29 PM
<ul><li><a href=""></a</li></ul>

01-28-2007, 01:31 PM
<ul><li><a href=""></a</li></ul>

01-28-2007, 01:34 PM
<ul><li><a href=""></a</li></ul>

01-28-2007, 01:36 PM
<ul><li><a href=""></a</li></ul>

01-30-2007, 05:46 AM
i usually take my parts there...<ul><li><a href="">Eurostuck</a></li></ul>

02-27-2007, 05:15 AM
here's the link to a little howto

to change your lamps from the power mirror switch to leds...<ul><li><a href="">link</a></li></ul>

02-27-2007, 02:01 PM
A smart-aleck way of suggesting an archive search.

03-01-2007, 07:11 AM
from the A4 forum<ul><li><a href=""></a</li></ul>

03-10-2007, 02:24 PM
Credit to Trent Wakelin for these part numbers:

8A0 615 125 A (034Motorsports or VAG Parts)

993tt Big Red Calipers:
993-351-425-10 (left), 993-351-426-10 (right)

Porsche 928 GTS front calipers
Porsche P/N -928-351-423-03 L, 928-351-424-03 R

Later A8 ROTORS (323x30, 5/112)
4D0 615 301 A or J (A was superceded by J)

Bolts, long (caliper to bracket, x4)

Bolt, short (Strut to bracket, x4)
N 100 880 03
Bolt size is: M12x1.25x25mm

Vibration dampers 44 mm (x4)
965 351 096 00

Vibration dampers 36 mm (x4)
964 351 096 01

Wear Sensors (x2)

Wear Sensor holders (x2)

Brake lines (x2)
443 611 707 C (rubber OEM, M-F, 405 mm long)
Or custom stainless steel


03-14-2007, 06:55 PM
<ul><li><a href=""></a</li></ul>

04-03-2007, 10:55 AM
UrS-car owner and cool guy Mario Pott from the Bronx brought this to my attention. Looks like something we may all need at some point.

Enjoy.<ul><li><a href="">Procedure to remove heater core without removing the console</a></li></ul>

04-11-2007, 03:36 PM
<ul><li><a href="">Link to S6 Plus / Euro center tail ight instalation procedure.</a></li></ul>

04-20-2007, 05:05 PM
<ul><li><a href="">Full bolt specs</a></li></ul>

Jason Teller
04-26-2007, 07:11 PM
The link should be good enough.

05-17-2007, 11:16 AM
<ul><li><a href="">Courtesy of</a></li></ul>

05-19-2007, 05:02 AM
<ul><li><a href="">PDF Blower Motor R&amp;R Instructions</a></li></ul>

05-20-2007, 06:43 PM
Found these via searches. Thought it would be tidy to have them here.

06-04-2007, 09:34 PM
First off, let me say that I should only get credit for posting this, as I didn't write it. I got this off the old S4 list from a LONG time ago, and had the instructions on paper.

I figured they should be part of this thread.


I'd like to contribute the following piece for the Avant owners out there.


The tailgate trim on the Avant is absolutely the most sinister piece of interior trim I have ever removed. It is simply Evil. I'd like to contribute the following explanation to the Avant owners. Take my word, and archive the following description. Otherwise, you will most likely break various parts off your tailgate trim if you ever need to go in there. TRUST ME!!!

First, remove the two screws holding the two hooks for the sun screen. Then, unsnap the top moddle piece in four locations. Unsnap L and R side plastic pieces by pulling the trim pieces towards center.

Next, remove the 2 black scres underneath the latch and one screw on each side of the bottom panel. Pop out the secret flap type compartments of the lateral parts of the carpeted section with a flat screwdriver. These hidden compartments correspond to an area behind each tailight. Unscrew one HIDDEN screw behind each secret panel.

Now, at the bottom of the handle trim below the torx screws are two very small holes. Find a thin long object like a nail and push in to the two holes. (I told you this was evil). When you've pushed them down far enough the handle trim will simply seperate from the tailgate trim. YOU DO NOT NEED TO TAKE OUT THE TORX SCREWS IN THE DOOR HANDLE.

Now, careful pulling in different sections top and bottom should free up the whole thing. You can also reach in and pinch the inner portion of the clamp while pulling that portion of the panel out. The whole thing falls right in to your hands.

Re-installing, should be somewhat of a reversal of the removal procedure found above.

Hope this helps someone out there.

06-06-2007, 08:14 AM
<center><img src=""></center><p>

06-26-2007, 08:50 PM
<ul><li><a href="">OEM Euro</a></li></ul>

07-27-2007, 03:43 PM
Prevent hose blow-off by using the best clamps for your boost system.

Breeze CT clamps from; part number, and number of each needed:

(3) CT-350
(2) CT-300
(1) CT-250
(1) CT-175
(2) CT-9416
(1) CT-9412<ul><li><a href="">Replace your clamps - it's a Breeze</a></li></ul>

07-28-2007, 08:32 AM
<center><img src=""></center><p>See the gold clip in the photo? The clip is to the rear of the assembly. Slip a screwdriver under the rear of the panel and push (kind of hard) and then lift out.

08-20-2007, 04:09 PM
There are brackets spot welded to the body at both ends of the steering rack. There can be fatigue cracking in the brackets or the body. There are new brackets available as:

4A1-809-321 Updated Passenger Steering Rack Bracket

443-809-489 Updated Drivers Side Steering Rack Bracket

<a href="">Click here to link to audi//s//scott's post with photos of the brackets</a><ul><li><a href="">Installation procedure with photos here</a></li></ul>

08-29-2007, 09:52 AM
<ul><li><a href="">Courtesy of Marv Gomez and his instructor</a></li></ul>

10-11-2007, 03:42 PM
See below:<ul><li><a href=""></a</li></ul>

10-21-2007, 07:43 AM
If you have a four spoke air bag steering wheel in your UrS4 and you can get a hold of a three spoke airbag sport steering wheel from an UrS6 or an early B5 A4 for a decent price (e.g. $120 for the wheel and $150 for the air bag), then you really owe it to yourself to convert the steering wheel. The feel of the car is amazingly different with the thicker-rimmed sport steering wheel. Follow the link to Steve Young's detailed instructions.<ul><li><a href="">Link to the instructions</a></li></ul>

10-27-2007, 09:15 AM
<center><img src=""></center><p>No. 15 is the after run switch
No. 16 is the MFTS.

You need to use a 29 mm deep socket to change the MFTS. See "procedure" in the link below.<ul><li><a href="">MFTS replacement procedure</a></li></ul>

11-08-2007, 07:57 AM
This is a good one. Lots of details and photos.

A real keeper<ul><li><a href="">Maciu's CPS replacement procedure</a></li></ul>

11-21-2007, 08:03 PM
<ul><li><a href="">Link to the procedure thread (check the comments too)</a></li></ul>

11-21-2007, 08:07 PM
Remember make any comments in the thread in the link, not here.

Lots of people just tighten by "feel". Personally, I like the "new" procedure detailed in the thread below.<ul><li><a href="">Link to the reasons why plugs can get loose over time</a></li></ul>

11-21-2007, 08:09 PM
Again, add any comments to the testimonial thread not here. (Thanks).<ul><li><a href="">Link to the testimonial thread.</a></li></ul>

- GT Style -
11-27-2007, 07:26 PM
Here's a link to "HVAC climate control secrets"<ul><li><a href=""></a</li></ul>

12-16-2007, 10:21 AM
See link below.<ul><li><a href=""></a</li></ul>

12-16-2007, 07:05 PM
See link below from<ul><li><a href=""></a</li></ul>

12-17-2007, 08:37 PM
<A HREF="" target="_blank">Here's</A> my method as I didn't like the idea of drilling holes into a license plate.

A few notes:
1.) Change your license plate bulbs <b><u>before</u></b> installing the S6/S6+ center section as they're harder to get to than with the stock tails. An ideal time would be once you have the original plate bracket removed (for easiest access)

2.) Don't reuse the Butyl from the original lights, the stuff you want can be bought at any auto parts store and looks like <A HREF="" target="_blank">this</A>.

12-17-2007, 09:51 PM
<ul><li><a href=""></a</li></ul>

01-03-2008, 07:06 PM
There was some debate whether or not there was a write up, with Pictures, for replacing the ignition switch.

Since I found the Text Article very useful, I thought I'd put some Pictures to it and rework it a bit for future generations.

I'm referencing the How To by Franco Barber found here: <a href="">Original How To</a> and have done some direct copy and pasting where I could.

The Switch is obtainable at your local VW/Audi Stealership, I paid $44 including tax. Part # 4A0 905 849B. DO NOT get the cheap white replacement on this one. Get the Genuine VW/Seat/Skoda/Audi part which should be black. Rumor has it that if you cheap out and get the white one, you'll be doing this proceedure again in a year with another new switch. (There's a "once you go black," joke in there somewhere.)

<img src="">

Ok, here we go, Step by Step.

<b>Step 1:</b>
<B>DISCONNECT THE BATTERY! </B> Several very good reasons, I'll go into them later. Also make sure you have your Radio code if your stock radio requires it after loss of power.

<b>Step 2:</b>
You need to remove the Gauge Cluster. To do this Move the Steering Wheel all the way down, and out. Some ppl remove the Wheel, I didn't find it necessary. Put down a towel on top of the steering column to avoid scratches.

You remove the two screws from below the trim piece, then the screws holding the cluster into the dash it's self. Pulling the Cluster out of the dash has been described as a "Chinese Puzzle," Take your time. When it's out, rotate it forward and disconnect the plugs from the back and set it aside.

Whatever you do be careful of scraping the bottom of the cluster on the metal cluster mounts of the Dash. On the S6 cluster, there is an exposed Circuit board on the bottom of the cluster that YOU DO NOT WANT TO SCRAP (not sure about the S4 cluster.) This is also a reason for disconnecting the Batt. If you bridge two solder lines of this exposed board on the metal you will totally Fubar your cluster. (There is power to the cluster even if the ignition switch is off.) If you smell burnt electrical componenents, it's too late.


<img src="">

<b>Step 3:</b>
To the right of the ignition switch and up a little bit is a flasher relay mounted to a bracket, with a cable that runs back and connects to the same harness that the ignition switch connects to. Remove the flasher from its mounting bracket and move it out of the way. It just pops or slides out. I didn't disconnect the harness from the flasher, just got it out of the way.

You can then use this bracket to hold a small pocket flashlight (like the one I got from Secret Santa of '07.) You can see how I did in the 3rd picture below. Thanks Secret Santa '07 :)

<img src="">

<img src="">

<b>Step 4:</b>
I removed the electrical Plug from the back of the switch before step 5. The reference article didn't do this; I just found it easier to get the switch out without the wiring harness there, as I have big hands.

I used a larger flathead screwdriver as a prybar. It popped right off with minimal effort. Since I had <b>THE BATTERY DISCONNECTED,</B> I didn't have to worry about welding myself or the screw driver to the dash. Which is always a nice thing.

<img src="">

<b>Step 5:</b>
The switch is held in place by two set screws. You will need a <b>Very Small Flathead screw driver</b> for them. I used a 3mm electronics screw driver.

There is some red loc-tite that keeps them from vibrating loose. Have some loc-tite handy before you start so you can lock them down again after you're done.

You don't have to completely remove the set screws to get the switch out. You can just back them out about 3-4 turns and still get the switch out. Press hard with the small screwdriver and turn to get through the Loc-tite.

The Switch will then slide backwards and you will be able to pull it out.

<img src="">

<img src="">

Here is the naughty broken one:

<img src="">

And here he's posing side by side for a picture with his much more well behaved and reliable replacement:

<img src="">

<b>Step 6:</b>
Getting the Plug / Wiring harness into the back of the switch was impossible when the new switch was mounted back in the dash first.

I ended up mating them, and then reinserting the whole thing into the bracket, then tightening the set screws. It's tight, but you can get it.

Don't forget to re-loc-tite the set screws. You can also use a small dab of enamel paint. (and no worry about sparks when mating the switch parts! Did I mention I disconnected the Battery?)

<img src="">

Note: no white switch anymore, just black!

<img src="">

<b>Step 7:</b>
Re-connect / Mount the flasher relay.

<b>Step 8:</b>
Re-connect the cluster and remount.

You will want to take the time to put some electrical tape or epoxy over the exposed circuit board on the Cluster. I also put electrical tape over the metal screw mounts and just ran the screws through it when I re-screwed in the cluster for future piece of mind.

This is also a good time to upgrade your dash lights to LED's or the 2W halogen version of the bulbs. You can get the LED's at <a href="">Super Bright LED's</a> Scroll down to Instrument Cluster LED's. There are several other online suppliers. Pick your favorite. You'll need 9 of them and I recommend red. LEDs are polarity sensitive, if you put one in and it doesn't light up, rotate it 180.

That's pretty much it. Not a hard job, but it can be a bit of a tight squeeze on some of the manuvers required.

I'd rate it at the difficulty level of a single bloody knuckle and two beers for the frustration of getting the cluster out without fubaring it (Ask Weldon how much my replacement was.)

Total time was under an hour and a half including picture taking.

nate @ 034MOTORSPORT
01-17-2008, 01:38 PM
We have everything from Stage 1, 1+, RS2, on up to Garrett GT series chipsets, and full custom tunes.<ul><li><a href=""></a</li></ul>

01-21-2008, 01:38 PM
General Procedures. YMMV.<ul><li><a href="">Link to throttle body removal/install/adjustment writeup</a></li></ul>

01-25-2008, 10:54 AM
Some people have complained that HIDs dont fire up after initial installation. The plug that comes with the VVME kit is easily mistakenly reversed.

Try reversing the plug. If that doesn't work try either swapping ballasts or bulbs, but it is more likely that the plug is installed the wrong way.

Good luck.<ul><li><a href="">Link to VVME HID DIY Writeup</a></li></ul>

02-04-2008, 01:50 PM

03-19-2008, 06:38 PM
<ul><li><a href=""></a</li></ul>

04-19-2008, 10:00 PM
<ul><li><a href="">Click for more info</a></li></ul>

04-26-2008, 07:08 AM
If you're on a tight budget and need to replace your fuel pump, here is the Walbro 255 GSS341 installation made easy. It is a $100ish option and can be considered an "upgrade" from stock. The numbers put this pump in between the Bosch 005 and 044 units, however let it be known that many have reported Walbro as "across the board" lifespan and quality wise.

YMMV, so I recommend at the very least purchasing the Walbro from a reputable reseller who backs their products with some type of warranty.<ul><li><a href="">Walbro 255LPH GSS341 // Fuel Pump DIY &amp; Other Fuel pump options</a></li></ul>

05-13-2008, 07:29 PM
This should help finding and understanding some of the devices that the AAN 20vt needs to run.<ul><li><a href="">Click here for diagram and hyperlinks to device information</a></li></ul>

07-23-2008, 07:18 AM
From alpinab7's post

<img src="">

08-05-2008, 09:21 PM
I didn't write, but thought it would make an excellent reference guide.

Follow the link below:<ul><li><a href=""></a</li></ul>

08-12-2008, 10:04 AM
Compare prices across many different retailers<ul><li><a href=""></a</li></ul>

09-04-2008, 06:34 AM
Well that one is dead. Try this <A HREF="">Audi VIN Decoder</A>:

<A HREF=""></A>

Linc's S4
09-22-2008, 03:18 PM
Recently my sunroof would only open a little way then stop. Then to close, it would go through the close cycle, open the back, then close again, then shut down.'

I tried disconnecting the battery, tried cleaning the switch, but to no avail.

The next thing I did was to remove the motor assembly.

First, pull the switch cover off, unplug the switch plate.
Then get the torx bit #25 and remove the three screws.
The motor will then come out in your hand easily.

Replug your switch and cycle the motor with it resting in your hand, the smaller drive gear should rotate constantly for about 5 seconds then click off, the bigger timing sprocket should turn in jumps with every one revolution of the main gear, this is the timing gear, if it stops or is stuck then the drive will stop as well.

Mine had a bunch of crap laying around the drive gear and timing wheel and I suspect that the junk was interfering with the timing wheel.After cleaning the housing out I then sprayed a lubricant ( NOT WD 40 ) on the timing wheel and under the drive gear, cycled it a couple more times, then reinstalled the motor.Then ran the sunroof back and forth, happy with my success, I reinstalled the switch gear and cover plate.

On a side note, I noticed that nowhere is it mentioned that when operating the sunroof manually, you should pull out the red drive connector part way (Don't pull it out all the way, you will have to re-time the driver ), this disengages the motor from the drive mechanism, you can strip out the allen driver if you don't disengage the the driver.


09-23-2008, 05:59 AM
Cleaned up icky formatting on doc and reposted...<ul><li><a href="">Headlight lens cleaning &amp; replacement repost</a></li></ul>

09-25-2008, 07:04 PM
<img src="">
1 - Crossmember II - Note different types - Mount on differential
2 - Gasket - Always replace - Remove protective backing and install on CV joint
3 - Crossmember I - Note different types - Continuously angled edge points toward front of vehicle
4 - Bonded rubber bushing
5 - Self-locking nut - Always replace - 60 Nm (44 ft lb)
6 - Driveshaft - Before disconnecting, check colored markings and/or put mark on flange shaft and driveshaft
7 - 55 Nm (41 ft lb) - Always replace
8 - Crossmember - Note different types - Provided with bonded rubber bushing - When mounting the crossmember, make sure the four holes in the crossmember are aligned as concentrically as possible to the stay bolts. - Align the rear axle after repairs.
9 - Self-locking nut - Always replace - 45 Nm (33 ft lb)
10 - Wiring harness bracket - Connect to trapezoidal arm
11 - Wiring harness For ABS wheel speed sensor - Install in bracket - Do not pinch when mounting on trapezoidal arm
12 - Trapezoidal arm - After removing, installing or replacing: check toe and camber
13 - Hex nut - 10 Nm (7 ft lb)
14 - Bolt - 45 Nm (33 ft lb)
15 - Self-locking nut - Always replace - 45 Nm (33 ft lb)
16 - Bracket - Welded onto floor
17 - Bonded rubber bushing - Coat first with acid-free lubricant - Press into bracket by hand
18 - Transverse link - Left and right sides different - Check camber after replacing
19 - ABS wheel speed sensor Press into wheel bearing housing to stop
20 - Wheel bearing housing
21 - Bracket for ABS wheel speed sensor wire
22 - Self-locking nut - Always replace - 40 Nm (30 ft lb)
23 - Washer
24 - Self-locking nut - Always replace - 45 Nm (33 ft lb)
25 - Self-locking nut - Always replace - 85 Nm (63 ft lb) - Tighten with vehicle standing on wheels

09-27-2008, 08:02 AM
shown in this post:<ul><li><a href="">click here</a></li></ul>

10-07-2008, 05:07 PM
Courtesy of Nate P. (ImQuattro)<ul><li><a href="">Sie muessen hier klicken</a></li></ul>

10-13-2008, 07:34 PM
KATE helpfully lists the dimensions of all the OEM hose clamps - while there may be an odd error or discrepancy, this is what it seems to show for clamp requirements...

<b>Major Hoses:</b>
MAF-&gt;Turbo: (1) 70-90 (1) 60-80
Turbo-&gt;Crossover-Pipe: (1) 50-70 (1) 60-80
Cross-over-&gt; IC (2) 60-80
IC -&gt; TB (1) 60-80 (1) 70-90 (1) 23-35

<b>Smaller Hoses:</b>
ISV (4) 25-35
WGFV (5) 12-25
BPV (2) 25-35 (4) 8-12

<b>Illustrations for reference / confirmation: </b>
133-70 Vacuum hoses and connecting parts
133-73 Throttle body
133-76 Mass air flow sensor
145-25 Turbocharger / Wastegate
145-55 Intercooler


11-09-2008, 07:04 PM
The OEM sun visor clips can break, and are unfortunately NLA at the dealer. Here may be an option for some of us...

See link below:<ul><li><a href=""></a</li></ul>

11-21-2008, 12:46 PM
The Bilstein strut insert is an inverted damper. The damper part with the gas charge is located at the top inside the chrome shaft. The yellow lower part of the insert is hollow and encases the piston rod and bump stop. There are vents in the bottom of the hollow shell to let air in and out as the damper moves up and down.

By design, it acts as an air pump. On compression, the damper part pumps out past the seal in the strut cap. On rebound, any moisture on the chrome shaft is sucked past the cap seal into the strut housing. Eventually, enough water collects in there to partially fill both the strut housing and the hollow insert shell.

When the temperature drops, it causes the water to freeze. The damper bangs against the ice and you have a rigid suspension. After a while doing this, the banging generates enough heat to melt the ice and the problem seems to go away.

I experienced this behavior with Bilstein HDs and stock springs. Over time, I replaced 3 inserts under warranty until I figured out what was going on.

<img src="">

Vent holes in the strut insert are here:

<img src="">

Here's my simple fix? I drilled a hole in the bottom of the strut housing to allow the water to drain. About a 3/32" drill bit. The hole has to go in at an angle so the drill can get past the axle. Be careful that the drill bit doesn't go through and into the insert. It won't affect the functionality of the insert but you won't be able to exchange it under warranty if it's got a hole in it. Or, you could remove the inserts before drilling.

<img src="">

Also, check the condition of your strut bellows. they keep water off the strut shaft.

- GT Style -
12-04-2008, 10:10 AM
<ul><li><a href=""></a</li></ul>

12-16-2008, 04:52 PM
<a href=""></a> - My new low price leader. Pricing varies day to day. Free shipping over $50. They list manufacturers and allow you to choose. Bought some parts for a timing belt job. Quick delivery, parts as advertised.

12-16-2008, 04:58 PM
<a href=""></a> - Good for remanufactured parts. I've bought brake calipers here. Good prices &amp; service. Shipping charges.

12-16-2008, 05:15 PM
<ul><li><a href=""></a</li></ul>

01-07-2009, 07:22 AM
write-up by zwoobah<ul><li><a href="">Click here</a></li></ul>

01-19-2009, 05:43 PM
<ul><li><a href="">Original Thread</a></li></ul>

02-13-2009, 01:35 PM
Thank you Charlie Smith for this one!<ul><li><a href=""></a</li></ul>

03-02-2009, 11:11 AM
For just a little more money than a chipset + VMAP option you can go w/ a plug n play standalone ecu like the VEMS unit.

I got my VEMS set up from EFI Express and had outstanding results with it.

Safer tune, ability to log runs and outstanding customer support.

Just my .2 cents.<ul><li><a href=""></a</li></ul>

03-07-2009, 07:53 PM
After losing a considerable amount of coolant and not wanting to chase leaks hose after hose, I redid all of the hoses, heater core, sensors and plastic stuff in my cooling system. This is a compiled list of numbers and some info I didn't find anywhere else here, yet.

Thanks to Kevin Day (kday) for his thread from a few years ago with part #'s (which jump started my project), and others threads with all of the info that made my project a success!

MOST IMPORTANT THING HERE: SEARCH! If you haven't already. There is a huge amount of how to/tips and tricks info on this site about this stuff. A little SFTA and you will have a lot less headaches!

Things I have omitted from here:
-The block to turbo hose connection at the freeze plug, the o-rings on the water manifold and the metal pipes, as they are not common leak points.
-I have omitted the radiator and head gasket part numbers, but they are widely available (FAP99 and AutohausAZ are good sources).
-I also have omitted the water pump as it should have been replaced with the timing belt.


4a0 121 101b - radiator to expansion tank and water manifold
4a0 121 109a - expansion tank to water pipe
4a0 121 109b - water pipe (from x-tank) to radiator
4a0 121 055c - thermostat housing to water pipe
4a0 121 055d - water pipe (from t-stat housing) to radiator
N 020 262 1 - banjo fitting on water manifold to turbo coolant line. - I just bought an 8" piece 5/16" bulk line from my FLAPS
034 121 063 - block (behind t-stat) to water pipe (heater/after-run pump line)
4a0 121 082 - after-run pump to water manifold


4a0 121 081 - water pipe (heater/after-run pump) to after-run pump
4a0 819 373c - heater pipe to heater control valve
4a1 819 373f - bleeder screw assembly (hose)
4a0 819 371c - heater core to 'T' fitting (HVAC sensor port)
4a0 819 371b - 'T' fitting to heater flange (on back of block)


4a0 819 809 - heater valve
034 121 143e - coolant flange (plastic)
N 900 351 03 - coolant flange o-ring
035 121 113b - thermostat (87'C)
035 121 119 - o-ring t-stat housing
074 121 121b - t-stat housing
443 819 031c - heater core
034 965 561c - after-run pump
4a0 121 403 - expansion tank
025 121 142 - clip for HVAC sensor in 'T' fitting
0 132 801 003 - flap motors in heater box (see notes below about this)
4a0 959 101a - blower motor
431 819 225 - heater box gasket (seal between box and bulkhead)


191 959 481c - 2 stage fan switch in bottom of radiator (stock temperature ranges)
054 919 369b - after-run pump switch
034 919 369c - MFTS (Multi-Function ThermoSwitch)
034 919 369m - coolant temperature sensor (ECU)
025 906 041a - HVAC sensor (in 'T' fitting)


Some things that might be of assistance:
-The first place to look for coolant leaks that I have found are the after-run pump, expansion tank, t-stat housing/seal, heater flange, heater valve, turbo coolant line and HVAC sensor 'T' fitting.
-I had to cut off a lot of my old hoses as they were original.
-The block to water pipe hose behind the thermostat is easier to work with by removing the water pipe. This pipe is bolted on to the transmission bell housing with a 16mm head bolt.
-The replacement heater core I got has slightly smaller diameter intlet/outlet ports. This is fine as the hose clamps can bite down enough to make a good seal.
-I replaced everything in the heater box while it was out 'cause I didn't want to take it back out again! It is not hard, but is a bit time consuming. It can be removed without removing the center console. Follow the Bentley procedure, but instead of removing the console, do this:
1)remove glove box and both footwell ducts.
2)remove 90' defroster air duct connector tubes (they snap out)
3)pull heater box out just enough to get at the red and blue flap motor plugs and unclip plugs. I used a small pick with a 90' bend at the tip as it was hard to get my hand at the right angle to unclip them. Some say that removing the radio makes it easier to get at the plugs but there is a metal bracket in the way on my car
4)heater box can now be removed.
-I used bulk closed-cell foam gasket material from Home Depot for the footwell ducts, panel duct and heater core seals.
-When rebuilding the heater box, I opted to use one type of flap motor. Audi lists a different part number for each of the three flap motors (hot-red, cold-blue and fresh air-black). They are all the same motor with different color/style plugs. Each motor has a different price ranging from $60-$200. I saved about $170 by ordering 3 of the cheapest one (the fresh air motor) and clipping the old plugs off of the old motors (with enough wire left for splicing!) and soldering them on the new motors.
-I used silicone RTV sealant to seal the heater core opening. It stinks. After 3 weeks, it has 'gassed out' a lot, but I can still smell it. Probably there is something better out there.
-I used for my dealer only parts source. They are the least expensive I have found.

I hope this is useful.

nate @ 034MOTORSPORT
03-08-2009, 10:01 AM
<center><img src="|phpThumb/watermarks/034watermark|C|20|0/hash/0a56608f6f7930121ee034e53c1571b8/src/images/SilHoseSetC4S4.jpg"></center><p><ul><li><a href="">10 Peice silicone hose set for UrS4/S6</a></li></ul>

04-05-2009, 08:31 PM
Everyone should read ALL of these.<ul><li><a href=";name=News&amp;file=index&amp;catid= 6&amp;topic=&amp;allstories=1">Click here</a></li></ul>

Dead link.

07-27-2009, 10:32 AM
Early production vehicles had a Bosch bypass valve with the number ending in 108 or Audi 710A which due to problems would eventually be superceded by a Bosch 114 or Audi 710N. This valve was far better in performance but still not completely reliable especially under modified conditions.

MTM did extensive research on various bypass valves for their 400 -500HP kits and came up with the Bosch Sport Valve 110 being the best in performance and durability, even over more expensive aftermarket valves. At JHM we also tested various options and concur with MTMs findings. With the Bosch Sport Valve the boost recovery and throttle response are enhanced significantly and since it is dimensionally the same as the original the installation is simple.

As stated in Audis technical bulletin dated Dec. 8, 2000 the bypass valves should be replaced should the following occur: Groaning or howling noise from engine compartment when accelerating during partial load between 2500-3000 RPM, or Rattling noise when decelerating between 2000-3000 RPM, which may be caused by the internal diaphragm of the charge pressure bypass valve producing pulsating noises.

While I was originally told that the valve could be found on 993TTs, I am unhappy to report that is FALSE. the 993TTs use the Bosch 108 valve (branded 710A)

I found my 110 Sport Valve by doing a part search on a 2000-2005 Saab 9-5 Aero.
The 110 Valve comes stock in the Saab 9-5 Aero (or any Saab with the B235R motor: Viggens/Aeros)
There is no Audi part number for this valve.
I purchased mine for $58+tax ({embeddash}3-SEDAN-005&category=All&part=Charge+Air+Bypass+Valve)
Charge Air Bypass Valve

0 280 142 110
The "Heavy Duty" version of this valve has a heavier diaphragm that helps prevent the "hooting" sound when the engine decelerates because of a weak or leaking diaphragm and the "Standard" version does not have the heavier diaphragm.

03-29-2011, 10:06 AM
Looking for front console removal procedure on a 93 S4. The link here in the FAQ is gone. Any other resources? Thanks.

03-29-2011, 02:26 PM
Well it had to happen. Somebody finally posted *into* the FAQ after 2 years and 11 days after the switch from Kawf to vBulletin. vBulletin is a nightmare for a FAQ because it bumps these older FAQ posts to the front instead of letting them stay in the background where they should stay. Had to happen.

The procedure you are looking for was reposted on another popular Audi website who's name can not be mentioned here.

Good luck.

10-28-2011, 03:18 PM
any1 know the removal procedure for the front seats on a 1992 quattro v8?? or have successfully done it?? if so lemme know!!

Norbert Romeo Matashu
11-10-2013, 06:18 AM
Car Starts, runs for 2 seconds then runs really rough then dies.

I have a problem with my 99 a4 will start up and idle but once i rev it, it bogs down and stalls, i plugged the ecu comp in and it read that the injector circuits are stuck open on all 4 cylinders...what do you think the problem could be ????...thanks for any help

Car Starts, runs for 2 seconds then runs really rough then dies.

Norbert Romeo Matashu
11-10-2013, 06:19 AM
Car Starts, runs for 2 seconds then runs really rough then dies.

I have a problem with my 99 a4 will start up and idle but once i rev it, it bogs down and stalls, i plugged the ecu comp in and it read that the injector circuits are stuck open on all 4 cylinders...what do you think the problem could be ????...thanks for any help

Car Starts, runs for 2 seconds then runs really rough then dies.