I had 4 very dead O2 sensors on my recently acquired 01 A6 wagon w/ a 2.8 in it. The O2 sensors waited for a while as I made war with some very fun valve cover oil leaks. At one point I did set a miss as one of my earlier valve cover jobs flooded a spark plug hole with oil (Cyl 2.). After finally winning the valve cover war I replaced all four O2 sensors with generic universal O2 sensosr. All my O2 sensors are working fine except for Bank 1 Sensor 2 which is showing codes for stuck lean P2270 and stuck rich P2271. Any ideas out there on this.

One other this that is baffling is there is a wire attached (Spliced) to ECM side of the O2 plug on Bank 1 Sensor 2 and runs somewhere unknown. I went by the Audi dealer and they had no idea what this wire is for and told me it was not any sort of recall fix. He told me to cut the wire and see if the problem goes away. Will maybe but what if its there to keep the car from exploding? Or maybe there for some real reason? Any body have any idea why someone would attach a wire to the O2 input wire on bank 1 sensor 2. And if this wiring could cause a P2270 and P2271 codes (Stuck lean Stuck rich)

 

I have explored the tapped in wire a little more closely. What the wire taps into is the the green and yellow O2 heater wire of Bank one Sensor 2. This green yellow wire goes to one of the white O2 heater wires. Starting here the tap then heads to a plug on what looks like a electrical unit attached to a hose next to the MAF sensor (Right fender area.). From the emissions tag I think it maybe something called a leak detector pump. Here the wire again taps into a green yellow wire. This tap then proceeds to be routed up over the engine and into the firewall. Behind the firewall the wire disappears into the dash-wall. Anybody have any idea why this was done or if this is anything that can cause a P2270 and P2271 code set?