Oxygen sensor bank 2 sensor 2.

[DelisleII]

New member, first thread
Please help me!

Have a 2001 Audi a6 2.8l

Check engine light is coming on immediately after reset, p0056 and p0156 every time, Thought for sure that the o2 was dead, replaced it and the light comes back immediately with the same codes. I put my scanner on it and see all the fuel trims toggling and the o2 sensors moving. Bank 1 sensor 1 is leaning itself out while bank 2 sensor 2 will not move from .435mv. I checked at the ECM connector and I have voltage at the heater circuit (pins 1 and 2) which rules out fuses, and I'm showing .468mv and 55ohm at the signal wire. the ground wire to the ground on the battery is showing 1 volt and a half ohm. I am at a loss because I'm not sure what the signal and ground should be reading. But I figure it's correct since I'm not showing out of limit which would show a broken wire.

At the signal wires on the o2 sensor connector I have 10ohms which is also normal. Why am I getting no change in the signal?!?

[DelisleII]

Update! Ok so followed by some research, I found that left and right bank o2 sensors are the same part on both sides. I figured I would try to swap the connectors under the hood and see if the code moves.. However when I got under there I noticed that they are all the same connector. (what one is for what sensor?) after googling Audi forums for a bit I found a diagram someone posted with just that information and alas!!!! The connector for the new bank 2 sensor 2 was actually plugged into bank 1 sensor 1 at the ECM. So the car was taking bank 2 sensor 2 readings and feeding them as bank 1 sensor 1 readings. Explains the lean condition on bank 1 and the rough idle. The guy I had throw the o2 in for $30 must have had the same problem with knowing what connector is what. (since ther are all the same shape and the replacements are only black!) he cut off the old sensor and reran the new one up and then disconnected the wrong one, left it unplugged and plugged the new one into it. Fortunately the unplugged one he left under there so I swapped the connectors and the car runs mint! Check engine light is off! However after driving on the highway home the light came back on with a new code. P0134 bank 1 sensor 1 no response. Why now that we actually have connection? I can't friggin win!!!