slobdogg

Hi guys, just getting opinions to see if I'm heading in the right direction with the solutions to error codes P0420 and P0430. Given that they're both up, does that tell you something that's not obvious to a noob like me? My plan is to start with replacing upstream 02 sensors; if that doesn't work then replace downstream sensors; if that doesn't work replace both cats.

Am I missing another (cheaper, easier) option? I just want to pass emissions testing is all.

djfllmn

iTrader: (1)

upstream o2s have nothing to do with reading cat efficency, and i believe the sensors are fine because they caught the cats are not working properly according to them

slobdogg

But wouldn't a bad sensor throw out the same code, with the sensor giving bad readings on the cat (because the sensor is bad). Thank you for the tip on the downstream!