My SES light came on the other day and we pulled the code with the tech II. The code came up P0420 420 oh boy... So guess what the code was for... clogged catalytic convertor Now what was GM thinking when they made that code

 

420 clogged cat huh. Was your truck smoking?

 

I was thinking the same thing. But the good news is now I have an excuse to buy that Magnaflow direct fit

 

That code could mean 1 of 2 things: clogged cat is one, but a bad O2 sensor (after the cat) is the other possibility. To check for sure swap the two rear O2 sensors (both of the ones AFTER the cats) from side to side...L to R and R to L. Clear the codes and wait for a code to be set again. You will egt either P0420 which means the cat OR P0410 which means that the O2 sensor is bad. IIRC, P0420 is the passenger side whereas P0410 is the driver's side. Just an FYI...been there, done that.

 

whaddya know.. his avatar is towlie.... do i see a connection? your learn that back in your hippie days touring with the dead?

 

well I guess my next question is does anyone have some o2's they dont need anymore cause they switched to sims or something!!