I have a 2002 Subaru Impreza RS. My check engine light lit up with the code p0136 which points to a rear oxygen sensor circuit malfunction. I had the rear oxygen sensor replaced with a original Subaru part, but the check engine light comes back with the same code. The work was done a week ago and I've cleared the code with my ScanGauge several times, but it keeps coming back. If it's not the part itself, what could it be?
Also, I don't know if this could possibly be related, but the light started a day or two after I had work done at the dealer. They replaced the head gaskets and the right rear wheel bearing. I went somewhere else for the oxygen sensor replacement because I thought it would be a simple job and that I didn't need to spend the extra money at the dealer.
Any suggestions as what to do next? Thank you.
Doug