isleblue65

No history on the battery, but it turns the motor over quickly even after the time I accidentally left the lights on for over an hour. It would surprise me if this car was so sensitive that it would require a new battery when the one that is in the car performs all other functions normally, and by any other standards does not act like it is near the end of its life. If this is the case, I'll replace this one with new and put the A6 battery in my wife's Subaru where it will happily function for another year or two problem-free.

I will swap out the battery for a known good one this weekend, clear the codes and report back. Thanks for the suggestion.

Edit: today at lunch when I started the car, the check engine light flickered for a minute and then came on. I just scanned the engine at lunch and came up with these faults:

2 Faults Found:

18084 - EPC Warning Lamp (K132) Circuit: Electrical Malfunction
P1676 - 35-00 - -
18098 - Malfunction Indication Light (K83): Electrical Malfunction
P1690 - 35-10 - - - Intermittent

Readiness: 0000 0000

I believe the second one may be an O2 sensor.

isleblue65

I took the terminals off of the battery posts, cleaned the posts and re-installed the terminals. I took the car to an auto parts store that carried the correct battery and had them load test my battery. It tested normal and strong and stayed above 10.5 volts for 15 seconds.

I removed the instrument panel, removed the connectors and re-installed them. I removed the APR chipped ECU, re-installed the stock ECU, allowed it to synchronize and then started the car. I shut it off, scanned with VAG-Com, cleared codes and started it again. The second scan came up with one engine fault code:

18084 - EPC Warning Lamp (K132) Circuit: Electrical Malfunction
P1676 - 35-00 - -
Readiness: 0110 0101

I re-installed the APR ECU and scanned the car after running it.

Results of that scan:



VCDS Version: Release 10.6.5
Data version: 20110930
Craig's A6 2.7t
Sunday,09,October,2011,17:45:13:50532

Chassis Type: 4B - Audi A6 C5
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
75 76 77

-------------------------------------------------------------------------------
Address 01: Engine Labels: 078-907-551-AZA.lbl
Part No: 4B0 907 551 K
Component: 2.7l V6/5VT G 0005
Coding: 06612
Shop #: WSC 30011
VCID: 2C4A0B08F690

1 Fault Found:
18084 - EPC Warning Lamp (K132) Circuit: Electrical Malfunction
P1676 - 35-00 - -
Readiness: 0110 0101

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8E0-614-111-EDS.lbl
Part No: 8E0 614 111 A
Component: ABS/EDS 5.3 QUATTRO D10
Shop #: BB 24334
VCID: 1C2ADBC8A630

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 4B0-820-043-MY1.lbl
Part No: 4B0 820 043 L
Component: A6-Klimavollautomat D64
Coding: 00160
Shop #: WSC 02325
VCID: 2358E0349B4E

1 Fault Found:
01274 - Air Flow Flap Positioning Motor (V71)
41-10 - Blocked or No Voltage - Intermittent

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 4B0-959-655-AI8.lbl
Part No: 4B0 959 655 H
Component: Airbag Front+Seite 1002
Coding: 00106
Shop #: WSC 02324
VCID: 357C2E6C25DA

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 4B0-907-487.lbl
Part No: 4B0 907 487 D
Component: Lenkradelektronik D01
Coding: 00103
Shop #: WSC 65535
VCID: 2D4C060CCD8A

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 980 MX
Component: C5-KOMBIINSTR. VDO D13
Coding: 02262
Shop #: WSC 19410
VCID: 870014A48FB6

No fault code found.

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: 4B0-962-258.lbl
Part No: 4B0 962 258 J
Component: Central Lock/Alarm D33
Coding: 15917
Shop #: WSC 02325
VCID: 30721F78DAB8

1 Fault Found:
01559 - Drivers Door
58-00 - Can't Lock

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr Labels: None
Part No: 4B0 959 760 A
Component: Sitzmemory D05
VCID: 2B480814F39E

1 Fault Found:
00668 - Supply Voltage Terminal 30
07-10 - Signal too Low - Intermittent

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 4B0-951-173.lbl
Part No: 4B0 951 173
Component: Innenraumueberw. D03
Coding: 00001
Shop #: WSC 02325
VCID: E0D22F384AD8

1 Fault Found:
01382 - Alarm triggered by Anti-Theft Sensor; Front Left
35-00 - -

-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4B0-907-357-AUT.lbl
Part No: 4B0 907 357
Component: LEUCHTWEITEREGLER D004
Coding: 00006
Shop #: WSC 02325
VCID: E5DC3E2C55FA

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8D0-035-1xx-56.lbl
Part No: 4B0 035 195 A
Component: Radio D00
Coding: 00205
Shop #: WSC 02325
VCID: 1E2ED1C0B02C

1 Fault Found:
65535 - Internal Control Module Memory Error
00-00 - -

End ---------------------------------------------------------------------

What is the next step?

Redneck Truck

You still didn't try a known good battery. 10.5v is not sufficient on a 12v system, so the test really doesn't prove anything. Is your check engine light on? I forgot. And if not, is the bulb present and good?

isleblue65

The battery is 13.5 volts at rest, and 10.5v is only while cranking, or under load from the resistance tester. Then it stays at 14.5 to 15 while running (because the alternator is charging it). This is my first modern Audi (my last one was a '79 Fox wagon), so I admittedly don't know everything, but the load test that was done would and did consider my battery to be good. My understanding is that a battery dropping below 12v while cranking is not an indication of it being a bad battery, unless it doesn't hold for 15 seconds or so under load or drops below 8 volts. Is this incorrect?

Yes, my check engine light is on, along with the EPC lamp.

Based on what I just said, you still suspect my battery?

Thanks

isleblue65

I don’t know if this new information will be helpful for diagnosis or not, but I’ll leave that up to others.
Today on the way to work it was 62° and rainy. When I started the car this morning, the check engine and EPC lights came on as usual. The lights stayed on while driving 30mph to 50mph, but while idling in traffic, the CEL faded to very dim and went off. It occasionally flickered and came on brightly for a second, but then faded so I could barely see it and then went out completely. Once I got back on the highway, the CEL came back on, though not 100% brightness and it stayed on until I got to work 20 minutes from home. EPC has stayed on 100% since last week.
The weather has been sunny and clear since the CEL came on until this morning, and this is the first time it has gone out intermittently. It just happens to coincide with the weather, though it may be completely unrelated. I was thinking MAF reading denser air potentially.
Question: is the CEL designed to fade on/ off like mine is, or is it a 100% on / 100% off indicator light? If 100% on/ off, I could guess this might be a bulb fault and I’ll change the bulb. If what I’m seeing is normal, then it’s anyone’s guess as to what is happening.
Thanks

Redneck Truck

Sounds like a bulb to me. Pull it apart and verify. I believe the cluster is very easy to remove, but never done it.

isleblue65

Cluster is super easy to pull. I did it just to remove and reset the connections (to see if it might reset something) and it took all of 10 minutes from start to putting the trim piece back on.

I'll probably replace all of the bulbs while I'm in there. Will report back.

Thanks

Redneck Truck

You'd probably spend more money buying all the bulbs than you'd spend on a good used cluster, but that's your call. Interested to see how it goes.

isleblue65

All of the "Bulbs" are actually surface mounted LEDs on a circuit board. No bulbs at all.

It's either a failure of the cluster or another problem.

This is the point where I either start throwing money at it by replacing one thing after another along the trail of possibilities, or start testing components that are identified within the fault code families.

Today after clearing my codes and then driving 30 miles, another fault came up which was low voltage in an 02 sensor. This was in addition to the 2 other engine codes I've already mentioned. The low voltage bank 1 (or 2 - can't remember) is something I've seen for several months off an on.

Next move is throw this background info on other forums I guess and see if I can get a few more heads working on it I suppose. Seems like it's playing its self out here.