1Wasserwerks

Hey gang,
Was only throwing one code, the p117c, behind cat, lean condition. Changed out the sensor, but upon driving and getting the readiness all in check (about 10 minutes of driving) popped a code again, same code relating to Bank 3 (driver's side rear cat) as well as a p3145 code as well.
I have just changed the oil and air filters at the 75,000mi mark, but I admit I have been lax with putting in any Techron additive. 93 Octane fuel is run all the time.
Am I looking at a pre-cat sensor issue as well or something else like an air leak throwing off these two codes?

Thanks in advance, Chris

Address 11: Engine II Labels: Redir Fail!
Control Module Part Number: 4E0 910 552 K HW: 4E0 907 552 A
Component and/or Version: 5.2L V10/4V FSI ª0020
Software Coding: 01060009190F0160
Work Shop Code: WSC 02313 785 00200
VCID: 2A5BEFAD856DF77110B-807F
2 Faults Found:

004476 - Bank3; Oxygen Sensor Correction; Behind Cat
P117C - 002 - Lean Control Limit Exceeded
Freeze Frame:
Fault Status: 01100010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 121429 km
Time Indication: 0
Date: 2015.07.13
Time: 15:31:45

Freeze Frame:
RPM: 1510 /min
Load: 23.9 %
Speed: 67.0 km/h
Temperature: 66.0°C
Temperature: 36.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 12.827 V

012613 - Oxygen (Lambda) Sensor B3 S1
P3145 - 002 - Signal Implausibly Rich - MIL ON
Freeze Frame:
Fault Status: 11100010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 121468 km
Time Indication: 0
Date: 2015.07.14
Time: 17:55:13

Freeze Frame:
RPM: 2850 /min
Load: 42.3 %
Speed: 78.0 km/h
Temperature: 104.0°C
Temperature: 42.0°C
Absolute Pres.: 990.0 mbar
Voltage: 13.081 V

NotoriousGLU

1Wasserwerks

Do you know which one is B3 S1? I have this code popping up 012802 - Oxygen (Lambda) Sensor B3 S1; Heating Circuit P3202 - 004 - Open - MIL ON.

I have no clue which one is it? If you could help I would appreciate it.

MP4.2+6.0

Front code is rich, so that shouldn't be any kind of vacuum leak that would be lean. Basic diagnostic would seem to be either fuel or sensor itself. Since it says implausible reading, I would lean toward sensor. If forward sensor doesn't know what is going on and ECU reacts to bad data (like cutting back mixture), rear sensor logically will then see the wrong exhaust output exiting cat.

Chris, see thread I am also linking in my other reply about sensor location. https://www.audiworld.com/forums/a8-...ssing-2861972/ Might help you assess yours too. PaulW mostly hangs on QW but posted that here. He is the audipages guy that goes back to his D2 days.

MP4.2+6.0

B3 S1 is (U.S.) driver's side, forward cylinders.

If this is an S8, location of the sensors is not fun. See this thread, and all the way back at the beginning an illustration of where they are. https://www.audiworld.com/forums/a8-...ssing-2861972/

For any sensor code involving an electrical error, be suspicious of the connector area, including car side of the harness. A lot easier to get at those than sensor removal. First just try unplugging and plugging back in, maybe spraying contact cleaner on it. W12's are known to have bad harness side connector wiring on at least first few years (had it myself) and a TSB for it, but not a consistent theme like that for S8's.

NotoriousGLU

Yes it is S8. I did some exhaust work on it and all of the sudden the heater for the sensor dont work. I will check connectors and clean it. right now but I am assuming it is sensor itself.

NotoriousGLU

As I assumed it is sensor itself I did clean the connection and same issue.