So I've searched through a lot of the forums and found some similar issues, but nothing that seems to match mine entirely. Check engine is on for 2 o2 sensors that are out, just found this out. No issues when I was driving. However now, the esp and the abs lights are on, when I accelerate in drive it doesn't start to move until around 2k or 2500 rpms.

I've seen coil packs as an option, MAF, vacuum leak, abs sensor on wheels possibly.

Just not sure where to start, any suggestions would be great. Thanks.

Also, this is a 2001 A6 4.2...

UPDATE:

Ok, another code pulled, P0600, miscommunication. Also have water in passenger side, both front and back, so from what I have read, the TCM is under passenger side, that could be related to the code and the water may be the main culprit. If wrong, let me know, front passenger seat out, and pulling up carpet.

 

Update 2: Ok, so water looks to be coming in through air filter area inside engine compartment. Tested all drains on sunroof, work perfect, battery water drain hole, clear and working. But when pouring a bucket of water across the windshield, noticed it running in by the front passenger kick panel and wiring behind the glove box, odd as hell.

Still need to pull ecm and check that, but now found some speakers not working and windows won't work with each door except drivers. Not sure if because of ecm issue or because passenger seat out until I can also look at the tcm... Too many damn acronyms.

Hope the water issue helps anyone else who may have come across it and wasn't the usual thing.

 

Update 3 I believe:

Ok, so leak I believe is fixed, but still testing to cover my butt. From what I understand, the passenger seat has the TCM underneath, which was nicely flooded. But my fault code was a P0600, which is the ECM, correct? Anyone feel free to correct me if wrong.

Also, now the stereo is not working correctly, is that affected by the ECM? If not, what exactly is, tried to search but either not finding the right combo of search terms or nobody has ever said. I see a radio fuse location in the panel, has (A6) in parenthesis, but no fuse, should there be? There is another for phone and radio, guessing that overrides it, fuse looks fine there.

Also, I see ECM under passenger seat, others say in engine compartment in black box with relays, any definitive answer?

Ok, further research has shown that the tcm getting wet can affect the code fault to show for ecu because it affects the rest. Also, water leak is in the pollen filter, not the air filter, geez, keep forgetting the sucker has that. So need to reseal the bottom of the pollen filter to stop the water, see some others have had similar issues. TCM dried out, no esp or abs light now, but radio still busted, ain't one thing it's another. Considering swapping out radio for ipad mini, wonder if possible, never use cd's anyways.

 

I had water coming into the passengers side after Safelite replaced my windshield. I checked all the drains and couldn't figure it out.. until I noticed that the "technician" didn't seal the plastic trim properly and water was getting in through the pollen filter that way.

I was lucky since I caught it early enough before some heavy rain - TCM was still fine.

As to your radio question:
You can replace the Symphony with an aftermarket radio supporting external devices (Android, mp3, Apple,etc) - however it can be painful. You need the proper wires that convert the Audi connectors to whatever Radio you buy, You will need some sort of cover to either fit the single Din or double Din (since Audi uses non standard Din sizes), you will most likely lose any steering wheel controls (if you have any) and you will lose in dash display for your radio.

 

Thanks for the note, good to hear I wasn't the only one with the pollen filter leak. Yeah, been thinking hard about whether I want to mess with the radio or not, sounds good, so maybe not worth the hassle. All my codes cleared, except airbag from taking passenger seat out, so hopefully a battery disconnect with clear it up.

Have to think about some other mods instead, new wheels are on the list, some other mileage needed repairs, just time for them. Thanks again.