I have a bad downstream sensor after i put on my cold air intake. It is the oxygen sensor 1 bank 2. I wasn't sure if I could just replace my cat with a test pipe and get the cel fix with it. If that would get rid of this problem or if i should just buy a new sensor? Also do you guys recommend the Generic kind such as bosch? thank you very much its my first day being a member i would appreciate it if somebody could please help me with some input.

 

So your secondary oxygen sensor is bad? What year car do you have? These "CEL fix" test pipes and high flow cats work very poorly on AP2s (read: they don't work). Your only hope is if you have an AP1.

 

Moved to Under the Hood.