My engine light was on awhile back...threw a code for downstream o2 sensor...so i replaced it and pulled the ground off the battery...drove to autozone and had no codes...

a week later my engine light has come on again except this time it wasnt my o2 sensor...it was PO420...i have no idea how to go about fixing this...i dont want my engine light to stay on like this...i have a 3" downpipe so idk why i have this code now and not before...

im gonna jack the car up and make sure i tightened the o2 sensor in good enuff and take a look...but other then that i have absolutely no idea on what to do and any help would be greatly appreciated...

 

by the way PO420 is CATALYTIC 1/1 EFFICIENCY
and i have no clue what that means or how to fix it...is it not flowing good? or flowing too much? its a 3" downpipe so idk...

 

Have you tried clearing the code to see if it comes back ?

 

That code usually comes up on cars that don't have a catalytic converter. If you don't have a cat, you either need the fouler kit, or a Staged Mopar Kit to erase the code. Most commonly, stage 1.

 

AHHHHH the fouler kit!?!?!? that makes so much sense now ur awesome lilsparkplug?!?!? when i changed out my 02 sensor there was like a (similar to a spark plug non fouler) thing threaded into the downpipe....the o2 sensor was in it and then that was threaded into the downpipe...makes sense now that i think about it...

BUT my new 02 sensor i bought at auto zone wouldnt fit into the non fouler.....so i just took it out and threaded it into the downpipe and i guess thats why i got this problem...

wow thx alot guys