I got a check engine light on so I checked hooked up my scan tool and got a trouble code for a rear oxygen sensor. Does anyone know where it is located and can I replace it myself. My S80 is a 2000 T6 twin turbo. I've changed O2 sensors on the GM vehicles before , just never had to on a Volvo yet. Car only has 129,000 miles on it.

 

the O2 sensors are plugged into the downpipe(s) before the catalytic converter and in the exhaust pipe after the cat. The front is used for fuel trim, the rear is to measure cat efficiency. Does your model have four O2 sensors? If so you'd need to look at the code to see if its bank 1 or bank 2 to know which one it is.

 

The exact code is ECM-2a2a

 

The rear oxygen sensor is mounted in the converter and they are a lot of work to change. Plan on removing the catalytic converter to get to it.

 

P0141 ECM‑2A2A Rear heated oxygen sensor (HO2S) Faulty signal preheating

List of Codes:
https://www.matthewsvolvosite.com/vo...nd-newer-codes