I finally got around to checking my check engine light. The code I got is a PO138 (I believe thats the number) I do however remember that it said bank 1 sensor 2 high volts. My question is, which oxygen sensor is this? Is this the one located in the Y-pipe. By the way, I have a 99 cali. spec. max. Any and all help would be greatly appreciated. The people at the autoparts stores dont seem to know jack so I thought I would ask the .org. Thanks in advance

 

it is the o2 sensor against the firewall on backside, i just replaced mine brought it to speedy lube and put it in for 50 bucks and bought sensor for 60bucks.