mh6558

Hey all, I just recently bought a 2002 S2K in April (116k mi) and the car runs great. I had to change the air pump because the check engine light was on and it would not pass smog at the time, but everything else appears to be in working order. I also have a Invidia exhaust on the car. However, about a week ago, my check engine light came on and read P0420. My question to all of you is, is it possible that I need to replace the O2 sensors rather than the CAT? This is a huge difference in price and to be honest, I'll sell the car before I but a new CAT. Subsequently, the car passed SMOG about a month ago. I would greatly appreciate any expertise. Thanks

Squirtle

Probably the sensor

pemex70

If you have a few s2k buddies ask to swap cats then sensors to see which is the problem.

If it is the cat they do go on sale used once in a while. No need to give your car an ultimatum.

klopez

you can find a used cat for like 200, or since u have a exhauast why not just ad a high flow cat.

usually 420 is a bad cat, unless both your 02 sensors are bad, but then again youll have a code for that too, and not just the 420 code.