Engine/Electrical Troubles

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Oct 4, 2008 | 11:50 PM

ThePagan

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Engine/Electrical Troubles

So there was a light rain today/tonight any my V6 '04 A4 Quattro was sitting outside. I get in it to go out for dinner and about 5 minutes into the drive my check engine light starts flashing and I get a sputter at idle with what feels like a loss of power. Being the good little Audi owner that I am, I turn around and limp home although the car did not feel like it was in limp mode. I've had a bad CP before and I figured this is what is was.

However, I just went back to it and turned the key to the on position (but did not start) and I noticed my dash lights when out when my head lights came on. They would come back on when my lights when out. Also, I heard what my roommate could only describe as a "Chewy noise." As in it was a moan/whine from what seemed like low in the passenger side of the engine compartment. It wasn't loud but it was noticeable and would happen when I would turn the key to the on position from off. Also, during all of this my radio won't come on. So, now I'm thinking it's something electrical (why wouldn't it be? it's out of warranty now). I was curious if anyone could offer up some troubleshooting tips I could try when I get back from my business trip on Tuesday before I have it towed to a dealer.

Thanks in advance.

Oct 5, 2008 | 02:07 AM

diagnosticator1

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Check the inside of the ECU box for water accumulation inside.

If there is water in the ECU box, remove the water and find the leak and fix that. You may need to replace what ever is water damaged if that is the situation.

Also, make sure the Central Electric Control Module, under the drivers side dash, is not wet from water dripping down from the ECU box above.

Oct 5, 2008 | 11:15 AM

ThePagan

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Re: Check the inside of the ECU box for water accumulation inside.

Super. I was thinking it may be something with the ECU.

I'm looking for instructions on how to get to that bad boy and I came across this:

http://www.goapr.com/Audi/support/ecu_a4_b6.pdf

Does it look fairly accurate? Just want to make sure before I start ripping things apart.<ul><li><a href="http://www.goapr.com/Audi/support/ecu_a4_b6.pdf">http://www.goapr.com/Audi/support/ecu_a4_b6.pdf</a</li></ul>

Oct 7, 2008 | 03:31 AM

diagnosticator1

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Yes, that is a good guide for removing the cover of the ECU Box.

Oct 7, 2008 | 10:02 AM

ThePagan

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Re: Yes, that is a good guide for removing the cover of the ECU Box.

Well I got the cover off and it appears to be bone dry. Problems with the dash lighting still persist. I haven't tried starting it yet either. Any troubleshooting suggestions? I'm trying to get an OBDII reader. We have one from dynoscan but of course we lost the media (not the serial number or the reader) and they want to charge $20 just to ship the media. And they wont even expedite shipping. In any event, just trying to think of anything I can try until I get that. I checked all the fuses and they seem fine. Didn't see any damage in the driver's side foot well, under the ECU.

Oct 7, 2008 | 12:03 PM

diagnosticator1

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A scan of the Central Electric Control Module and IC for any DTCs is required. ..

some of the symptoms are not related to the engine ECU, so a generic OBD scanner probably won't be of much use here. A VAG-COM is required to scan the various controllers other than the engine ECU. Besides a VCDS/VAG-COM, the dealers scan tool is able to interrogate the various non engine controllers.

It's possible for water to accumulate in the plenum and leak onto the CECM from the ECU box to plenum floor seal, from above. However, if that is happening, then there would be water evident on the drivers side carpet, or under the carpet. Check and make sure there is no water under the carpet. The Central Convenience Control Module is under the carpet, forward of the driver's seat, inside a plastic box.