# O2 Sensor Location - confused



## turbo+ (May 10, 2012)

I am new to the Audi community. I got at 2001 Audi A4 Quattro 2.8L - I have a check engine light and downloawded following information:

ddress 01: Engine Labels: 078-907-551-ATQ.lbl
Part No: 3B0 907 551 BP
Component: 2.8L V6/5V G 0001 
Coding: 07201
Shop #: WSC 06435 
VCID: 72EB66253E7FD28E927-5122

3 Faults Found:
17530 - Oxygen (Lambda) Sensor Heating; B2 S2 
P1122 - 35-00 - Open Circuit
17548 - Oxygen (Lambda) Sensor; B2 S2 
P1140 - 35-00 - Internal Resistance too High
17977 - Cruise Control Switch (E45) 
P1569 - 35-10 - Implausible Signal - Intermittent
Readiness: 0010 0001

So I found that the location of B2S2 is the O2 sensor on the driver side (left hand driver - not to get confused with English folks) after the catalytic converter and the plug is the brown one and the PN is Bosch #16069. So I checked the resistance on the heating wires going to the O2 sensor (pin 1 and 2) - it showed open circuit - so far so good.
I unhooked the brown O2 plug and pulled the wire down to under the car, but the wire with the brown plug goes to the passenger side - what the heck?!?! Confused - the wire with the green plug (#16067) goes to the driver's side cat and the wire with the brown plug (#16069) goes to the passenger side cat. I checked the resistance on the green plug (pin 1 and pin 2) and it was fine.
Did these ones got hooked up wrong by the previous owner, am I wrong? Shall I replace it the way they are or switch them (if they are wrong right now)??? Is there a way to check if they are wrong??


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## bzujus12 (Oct 29, 2016)

did you ever find an answer to your question? I'm getting the same codes, wondering how you ended up fixing it


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