Rep Power: 189

i have megan headers which delete the cat and have an angled cel eliminator on the second sensor which worked fine. but last night the cel came on so i hooked up the scanner and it says post cat o2 sensor slow response.

does this code mean the sensor is failing or something? or is it because i have no cat before the sensor?

i guess the wording is throwing me off...i would think it would say something about the converter not slow response from the sensor if it was the cat

 
Rep Power: 218

P0420 is the one you're thinking of. My car has that code. Well not anymore, I cleared it and I make sure the PCM doesn't run the monitors. If you have that code, it means the CAT isn't doing its job and both o2 sensors would have the same exact reading. Both my sensors work, but the CAT is basically toast at this point. I haven't had any personal experience with that, but I would think it's just failing, or getting close to it. If you know anyone with an available scan tool, you can check out the graphs for them.

 
Rep Power: 189

i dont have a cat...well i do but its down in the catback. but like i said i have an angled o2 sensor thing on the second sensor. so they shouldnt have the same readings