arjun90

One of the most interesting Christmas's of all times. Returning home from dinner and coolant was leaking through a crack in the coolant reservoirs. Using a VAG-COM yielded several Fault Codes. One of which attracted me the most was the Coolant Fan Control Module (J293). I noticed when turning on the car, both fans do not engage. While the car is idling in park position, and AC is turning on, only the driver's Fan is spinning and the Passenger Fan is not. What could be going on here?

I've already ordered a Genuine Coolant Reservoir and Cap from Audi. Other Fault Codes I received which were related to this are the following:

19497 (P3041) - Powertrain Databus: Implausible Engine Temp. Message from Inst. Panel (No Signal / Communication - Intermittent)

00735- Potentiometer in Positioning Motor for Air recirculation Flap (G143) / Open or Short to Plus - Intermittent

01039 - Coolant Temperature Sensor (G2) / Open or Short to Plus - Intermittent

18339 - Coolant Fan Control Module (J293) : Malfunction / P1931 - 002 - Lower Limit Exceeded - Intermittent

Vehicle Details:
Audi A6 C5 Quattro (2004) 3.0T
Miles: 139,286 Miles

arjun90

Will simply replacing the Coolant Reservoir resolve this problem? Is this a good first step to take?

johnkk

Yes, replace the reservoir first. Next replace the coolant temp sensor. Get a new clip, because you'll probably snap the current one when you remove the CTS. There is a decent chance that this will clear up the data bus and maybe even the fan module issue.

I'd check wiring to the fan and for voltage at the connectors with the A/C turned on and that the fan runs when powered directly with 12v from battery. Usual failure for fan control module is a default to high speed setting which sounds like a jet turbine with A/C on, but could fail differently.

I don't think I've ever used the recirculation setting on the A/C, so I would try to ignore. PITA to dig around in the dash, but may require fixing if the code drives you nuts.

arjun90

Thanks for the guidance. After searching the fault codes on the Rosstech website, I came across two different coolant temperature sensors. Which one should I try replacing first, the G2 or the G62? Also, where do I get a new clip? Thanks again.

arjun90

Also, is a particular situation when the passenger side fan should be running? I noticed when first starting the ignition and running the A/C at full speed, only the driver-side fan is running.

KingHamer

The codes should specify which sensor. I think the sensors are fairly cheap, might as well replace both right now! Also order extra retaining clips. You drop one and you'll be SOL. New sensors should have extra clips.

For the fans, I would just check the voltage to the fans. Maybe check fuses too

arjun90

Thanks, the fault code 01039 indicates that it is the Coolant Temperature Sensor (G2); I believe this sensor is located somewhere behind the coolant reservoir. The other sensor is related to fault code 19497. The VAG-COM I'm using only displays the fault codes and does not reveal solutions unless I search for them on Ross-Tech's website. The Ross-Tech website for Fault Code 19497 indicates one of the solutions is to replace the G62 sensor (19497/P3041 - Ross-Tech Wiki) Where is the G62 sensor located? Is there a schematic that I can follow when replacing the sensors. I'm thinking about replacing these sensors with Genuine Audi ones as the aftermarket (usually Made in China) seem to have mixed reviews.

Please let me know what you think, thanks again.

arjun90

Also which whats the fuse number for the fans; this is located near the instrument cluster panel (driver side) side of dash board, right?