Hello,

Just signed up today. Glad to be here. Not afraid to get out the tools, but I am not real familiar with the electronics. The basics are:

2005 A8 4.2L Quattro
69,388 miles

Check engine light went on last week. I did some basic research and bought a Vag-Com from Ross-Tech. Hooked it up and found 20 fault codes...and that's just for the engine. So now I am nervous and don't know what to do next.

I don't know if this is proper, but here are the codes:

Address 01: Engine Labels: 077-910-560-BFM.lbl
Part No SW: 4E0 910 560 J HW: 4E0 907 560
Component: 4.2L V8/5V G 0010
Revision: --H01--- Serial number: AUX3Z0DD756793
Coding: 0007773
Shop #: WSC 02313 785 00200

20 Faults Found:
16555 - Fuel Trim; Bank 1: System Too Lean
P0171 - 004 - No Signal/Communication - Intermittent - MIL ON
16558 - Fuel Trim; Bank 2: System Too Lean
P0174 - 004 - No Signal/Communication - Intermittent - MIL ON
18666 - Oxygen (Lambda) Sensor B2 S1: Signal Shorted to Heater Circuit
P2234 - 004 - No Signal/Communication - Intermittent
18663 - Oxygen (Lambda) Sensor B1 S1: Signal Shorted to Heater Circuit
P2231 - 004 - No Signal/Communication - Intermittent
16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal
P0106 - 008 - Implausible Signal - MIL ON
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 008 - Implausible Signal
16689 - Cylinder 5: Misfire Detected
P0305 - 008 - Implausible Signal
16688 - Cylinder 4: Misfire Detected
P0304 - 008 - Implausible Signal
16691 - Cylinder 7: Misfire Detected
P0307 - 008 - Implausible Signal
16686 - Cylinder 2: Misfire Detected
P0302 - 008 - Implausible Signal
16891 - Idle Control System RPM: Higher than Expected.
P0507 - 001 - Upper Limit Exceeded - Intermittent
16485 - Mass Air Flow Sensor (G70): Implausible Signal
P0101 - 004 - No Signal/Communication - Intermittent
16523 - Oxygen (Lambda) Sensor B1 S2: Response too Slow
P0139 - 004 - No Signal/Communication - Intermittent
16543 - Oxygen (Lambda) Sensor B2 S2: Response too Slow
P0159 - 004 - No Signal/Communication - Intermittent
16692 - Cylinder 8: Misfire Detected
P0308 - 001 - Upper Limit Exceeded - Intermittent
16687 - Cylinder 3: Misfire Detected
P0303 - 002 - Lower Limit Exceeded - Intermittent
16486 - Mass Air Flow Sensor (G70): Signal too Low
P0102 - 002 - Lower Limit Exceeded - Intermittent
16497 - Intake Air Temp. Sensor (G42): Signal too High
P0113 - 002 - Lower Limit Exceeded - Intermittent
16690 - Cylinder 6: Misfire Detected
P0306 - 001 - Upper Limit Exceeded - Intermittent
16685 - Cylinder 1: Misfire Detected
P0301 - 008 - Implausible Signal
Readiness: 0010 1001

The faults seem to center around the MAF sensor and the O2 sensors. My question is: how do I attack this problem? Where do I start? I think I read that the O2 and MAF sensors are warranty items up to 77k. But I am reluctant to take it into the dealer for fear of what else they might say. Any guidance is appreciated.

Rich Mayer
05 A8 4.2L Quattro

 

Def seems like a MAF problem.. Pull it and clean it, see what happens.. You can pull the connector whil running to see if there's a change too.. if not, its prolly bad.

 

Thanks. Would a problem with the MAF sensor cause all of those fault codes? Meaning if I correct the MAF sensor and clear the codes, the rest might go away?

 

It can cause alot of them.. I would start there

 

Hey again,

Took it to the dealer (hoping some items were warrantied). Dealer wanted to replace the MAF sensor. The dealer also performed silent recall replacement of the ignition coils. I bought the MAF sensor and installed it myself. Cleared codes, drove the car, and they came back. Well, 15 of the original 20 came back along with 5 new ones. Then I did some diagnostic work with the VAG and found that both pre-cat o2 sensors seem to be malfunctioning. My question now is: aren't o2 sensors covered by the dealer as part of the emissions control system?

Rich Mayer
05 A8L

 

the sensors generally go out without any warning. i have had this problem with my chevy engine codes which go off at strange times and then have to look up the codes to figure out the problem.

 

^^

BAN!