Issues:
1) CEL is on
2) Rough idle when in gear


Background:
Same issue occurred 6 months ago. Took vehicle to "Audi Specialist" who diagnosed & advised I had bad timing chain tensioner, which was replaced at a cost of $1700. The wires/plugs were also replaced. After tensioner/wire/plugs replaced mechanic advised car still not running smoothly. He wasn't sure what the issue was, but he was confident it "wasn't mechanical" in nature. Further troubleshooting by mechanic led to electrical issue...claimed wiring harness at "rear of motor" was melted and "caused computer to fry". Harness & computer replaced..at least that's what they advised. Picked up the car and it ran decently though seemed a bit low on power. Regardless, the CEL was off & I was back on road. Fast forward 6 months and the CEL is back on & the rough idle is back. I stopped by Auto Zone who hooked up diag machine and it spit 18 codes. Contacted different "Import Specialist who advised it sounds like an electrical issue and the fact that I got 18 codes vs. 2 or 3 may indicate I have 1 problem...not 18. he indicated in may be something as simple as a relay, but it's going to cost me another $200-$250 to have him diagnose and then there's the repair on top of that.


Codes:
P0134
P0154
P0160
P0300
P0304
P0305
P0306
P1196
P1197
P1198
P1199
P1300
P1392
P1421
P1425
P1435
P1472


Any help would be greatly appreciated...

 

okay for reference...

P0134 unsure... some sort of o2 sensor issue?

P0154 bad B2S1 o2

P0160 bad B2S2 o2

P0300 random misfire

P0304 cyl 4 misfire

P0305 cyl 5 misfire

P0306 cyl 6 misfire

P1196 bad B1S1 o2

P1197 bad B2S1 o2 (repeat of p0154?)

P1198 bad B1S2 sensor heater

P1199 bad B2S2 sensor heater

P1300 - unsure... fuel related misfire?

P1392 bad B2 cam position sensor

P1421 bad N112 valve

P1425 bad evap canister valve

P1435 bad secondary o2 pump relay

P1472 bad evap leak detection pump


LOT of electrical issues. Did you drive underwater recently? Was the ECU you got upgraded/chipped in any way?

 

I have not driven under water since purchasing the vehicle about a year ago. Though I have noticed that after it rains I'm finding standing water on e drivers door rocker panel. One further point of clarification...this is an Avant (wagon). I have a co-worker with a newer A4 sedan and he said there are fuses/relays under his driver side rocker panel. Not sure if I should try removing the plastic trim piece to gain access to whatever is under the rocker panel??

 

Not sure what you mean by rocker panel, to me that refers to an external piece on the door. But no matter, most of the relays are behind the knee bolster. There's 4 10mm bolts that hold it on and you can see whats back there. The fuses are much easier to get to, they're just behind a small panel you can see if you open the drivers side door all the way (90 degrees).

I would check in the ECU box, that can be a normal area for collection water and also has 1 or 2 more relays. You'll have to pull a wiper blade and get a few hard to reach screws but it's not too bad

 

It's probably not called a rocker panel...sorry about that..I'll try to attach a pic...bare with me...im a newbie...lol

 

Pretty sure there isn't anything under there...
That 'B' shaped panel in the left-center of the picture, sorta where the door meets the door frame, that's where the fuses are.
The knee guard/bolster just above the pedals is where most of the relays are. I would check the ECU box under the hood though as that has a tendency to fill with water and cause electrical issues.