Hey guys. 2003 A4 3.0 Quattro, just picked it up in December with 50k miles. Sat under a car cover all its life, tons of electrical issues as you can imagine. Wanted to address a couple.

For one, cruise control is completely unresponsive. I'm a professional tech, so please no "did you pull the stalk forward!?!" responses. From what I can find, the system consists of the stalk, steering column module, and then the ecu. Can't find a related fuse. I'm not concerned about a damaged ecu, though I went into limp a few times during wet/rainy conditions (a new E-box lid seal and drain cleaning seems to have solved that issue). I already had the steering column apart to replace an intermittently faulty turn signal stalk and didn't see any damage/bad contacts, and the new stalk did fix the turn signal issue, making me think it could be just the other stalk. Not a whole lot of info around on daig, mostly just retrofit stuff. My only other thought is that the ECU has been replaced before and wasn't coded correctly... Suggestions?

Second, I'm pretty sure my Symphony 2 has to go. Haven't picked up the removal tool yet to pull it out though. The first CD I popped into it seems to have jammed, and every time I start the car the changer cycles a few times and then it locks me out of CD mode. I feel confident that I can at least get the CD unstuck, but I'm hesitant for a few reasons. For one, I don't have this radio's security code, so if I'll be paying Audi for one, you better believe it'll be for a known-good unit. Also, randomly, I lose one side of stereo or the other while listening to either radio or my aux-cassette, and putting in a new head unit certainly couldn't hurt.

The dealer says the part number for my Symphony 2 is 8E0 057 195 G. Searching around, it is unclear what would be compatible. Logic would make me think anything out of a B6 A4 would work, but some websites have separate listings for 01-03 and 04-06. Does it matter? And certainly not out of an A6/allroad? How necessary is programming/coding on a direct replacement? Haven't invested in a Vagcom yet.

Lastly, I'm having severe timing belt anxiety. Only 54k miles, but over 10 years... Am I crazy, or justified?

 

Are either of your abs or traction control lights on?

The CD thing is kinda obvious.. Its stuck..

As far as losing channels, the speakers do not plug directly into your head unit. They plug into an amp behind the carpet on the right side of the trunk. They are notorious for going out, but you can pick them up on eBay for 20-50.. Otherwise your looking at $1000+ from Audi.

 

Good info on the amp, I'll see what I can find. Is intermittent loss of stereo a common issue, or do they usually just take a dump all together? And would that be a direct plug-and-play, or would I have the code the new one? Doing my best not to throw parts at this thing, but I'm not sure how I'd test it with my meter.

Yes, only during bouts of heavy rain, the car would show ABS/TC lights and go into limp and it would throw a code for Throttle Position Sensor: Implausible Signal. At first, the internet had me checking O2 sensors and the engine harness. Someone along the way mentioned water ingress into the e-box, which made sense considering my issue was in the wet, and I had admittedly cracked the e-box cover trying to access the SAI fuse at one point. Removed the foam seal, replaced it with a strip of butyl rubber, covered up the crack, reinstalled, and cleaned up the drains. No problems in the wet for months since. Otherwise, no drive-train related issues, so I think the ECU is OK...

 

Yes you will have to get the part number off the amp.. Audi has been doing the amp thing for years and years.. There have been many different amps used.. If you lose a channel pull the carpet back and bump the amp with your hand.. I used to lose everything and when I tapped the amp oy would come back..

If either the abs or traction control lights are on your cruise control will be disabled.. It could be anything from the break pedal switch, gas pedal switch, throttle position sensor, wheel speed sensor.. Or it could be one of several computers..

Do you have any drivetrain related codes?

 

No codes for a few months. Started with a pair of SAI codes, decided to check the SAI fuse in the e-box, then started throwing p2138 (TPS) in heavy rain and going into limp. Immediately solved the SAI issue when I found the pump was unplugged, took me a bit to determine/realize that I actually caused the rain issue when I cracked the e-box lid. Sealed up the e-box (very well) and cleaned up the drains for good measure, its been 2 months and many showers since I've thrown a code. I feel pretty confident my water ingress issues are solved and the ECU doesn't seem to show any signs of permanent damage. That's why I'm leaning towards the stalk (and that the turn signal stalk was bad, too). Maybe somebody has a decent wiring diagram so I can at least do some basic voltage testing?

Timing belt?

 

Does your traction controlor abs light stay on though?

 

Nope. No codes or abnormal lights/limp since I sealed it up, and I scan regularly. Also, cruise control was unresponsive before I caused the rain issue. Don't think a drowned ECU is at fault. I'll probably end up ordering the stalk and throwing it on, unless I can narrow it down some other way.

 

Besides the stalk the only other thing I can think of is the break switch. It has 2 contacts 1 normally open 1 normally closed.. One operates your break lights the other operates your cruise control.. I'm not sure if the cruise control side throws a dummy light tho..