Not your typical fan running issue

[4alarm]

Hello all - I'm new to this board, even though I've been following it for a while. I acquired my RS6 (in late July 09) and have been loving it ever since...

Until now..... Like others on this board, my fans have acting up and running on. They come on about 5 seconds after starting (high speed) and run maybe 3 mins after (low speed). When I got the car - the weather was hot, and I remember the fans started running not long after I got it. Then cold weather and the fans still running.... With hot weather, I thought OK - but not when it turned cold.

I've done all the searching and replacing of the parts that are associated with this issue.... at least that I could find.

First, we did the G2/G62 coolant temp sensor. Then the thermostat (and subsequent timing belt items). Then the secondary thermostat was replaced as well. We've checked continuity of the wires from the G2/G62 unit to the ECU. The most common fault we get is about the coolant system performance (2181 - not plausible signal). I don't have a Vag-Com (YET! - should be here this week...)

It has been at the dealer 5 times now. On the fourth time, someone drove the car (who hadn't before I guess...) and stated that it was way faster than the other RS6's they've dealt with. So - they put it on the computer and said they could tell it had been chipped (don't know by who). I didn't know this, and the previous owner in California apparently did not know about it either. They're cool with it (not telling my warranty co) - but it seems they want to blame the issue on the ECU now.

Could a chipped ECU cause this problem? (California tune????)
Dealer says they can't get a "factory" tune to re-flash it.
I can't afford to buy an ECU and swap it for testing.

I've been fighting this for 2+ months and I need some help.
Any advice????

Thanks - sorry for the long post.

[skribe]

...It has been at the dealer 5 times now. On the fourth time, someone drove the car (who hadn't before I guess...) and stated that it was way faster than the other RS6's they've dealt with. So - they put it on the computer and said they could tell it had been chipped

Don't know about the rest of it, but this sounds like the dealership looking for a way out of a difficlut diagnosis. Standard operating procedure for them to start looking for a way to blame the end-user.

I hope you didn't pay for all the most likely perfectly functioning parts that have been replaced so far?

[DHall1]

"the car is faster than other RS6s"

Tell me how many other RS6s this tech has flogged? And if he drives them on a routine basis flogging them.

I dont buy it at all.

Vagcom block 115 and report what the ECU is calling for and making for boost.

As for the problem. Can you post a clear example of what the fans are doing and when? Thanks

[RS6-4dr911]

I'm beginning to think the best solution to this issue is to wait until a code shows up or something overheats. Keep your eyes on the gauges and forget about it. Who knows what logic went into the on/off logic. If they go silent, then you can worry.

[4alarm]

to answer a few questions raised....

I paid for the $100 deductible one time for all replacements except for all the timing belt items.

not sure about how many cars he flogs but that's a good point.

as soon as my vag com comes in - I'll log that block. (once I read about how to do it... )

the fans seemed to start coming on more frequently as the weather got colder. they basically come on as soon as I start the car - cold or not - and then continue to run for about 3 minutes after I turn the car off. If I have the MIL reset, it lasts for about 2 days before the fans come back on as well as the MIL.

the car has been throwing codes. mostly the cooling system performance one (I think 2181? with not plausible signal), but also originally had it say - signal too low (or high, can't remember...) (when they replaced the G2/G62)
I've had the evap canister, brake booster and egt sensor all throw codes as well. Related??? (all but the egt sensor have been replaced.)

[4alarm]

Oh, and my coolant temp gauge has always run at normal. Even BEFORE we did the thermostat....

[4alarm]

OK - I finally have some time to play with the VAG-com and do some logging.

What should I be logging? And what's the best process for said logging.....


Any help is appreciated.
Thanks

[Aronis]

I have the same issue, just putting off going in for that service. I have managed it nicely with VagCom.

I just finished two things....replaced the front rotors and reseting that same error for the fans (for the third or forth time). I get an error code which makes the cooling fans run at full speed for about 5 minutes after shutdown, and at full speed while driving. This started in my car shortly after I had a temperature sensor changed on the back of the engine somewhere just in front of the engine block. I suspect the problem is simple a dirty connector and some day I'll take the time to remove the air cleaner/intake box (again) and unplug that connector and spray it with contact cleaner. That worked for more than a year so far for the drivers side airbag that gave me an error message.

The thing that surprises me is that the Check engine Light DOES NOT COME ON WHEN THAT fault occurs!?!?

Buy VagCom it's worth every penny. Even if just to reset the "Dirty Gas Cap Seal" slight evap leak thingy...funny when I first had that issue the CEL light came on also, but not any more. Perhaps my CEL has a fault LOL....

Mike

18613 - Performance Malfunction in Cooling System
P2181 - 008 - Implausible Signal

The code I had before they fixed the sensor was

19497 - Powertrain Databus: Implausible Engine Temp. Message from Inst. Panel
P3041 - 004 - No Signal/Communication - Intermittent

[4alarm]

18613 - Performance Malfunction in Cooling System
P2181 - 008 - Implausible Signal

This is the code I keep getting! I have a VAG-com and I have just been resetting the codes every couple days..... not sure what I should be logging to try and diagnose this.

I'm looking for anything to try!!

[Aronis]

dealer would be able to narrow down what the possible source of this code would be.

When I spoke with mine they implied it may be the new sensor which was installed, but I suspect simple connector currosion.