got a code that says O2 sensor Bank 1 Sensor 2. I'm assuming that Sensor two is in the rear but I don't know if it is left or right?

 

what kind of car and engine do you have?

 

I have an 01 Pathfinder. I found out that bank one is on the pass side. Almost was ripped off again. Mechanic told me that both sensors in the rear were bad. Went to the local parts store and they pulled the codes for free after the mechanic already charged me 75 bucks. He wanted to charge me $137 for each sensor. Found it onling, just the bad one for $45. hooked it up and all is well.......bad mechanics suck!