CEL Error Code P0420
JK Junkie
Joined: Dec 2007
Posts: 3,343
Likes: 3
From: Amherst, Ohio
Any update on this?
I got my cats out and they were fine. Unfortunately I ended up cutting them out instead of just dropping the crossmember.. the new ebay cats fit okay and might need some tweaking from an exhaust shop but I will be finishing the install soon and with all new O2 sensors to see if my code goes away.
I got my cats out and they were fine. Unfortunately I ended up cutting them out instead of just dropping the crossmember.. the new ebay cats fit okay and might need some tweaking from an exhaust shop but I will be finishing the install soon and with all new O2 sensors to see if my code goes away.
Thread Starter
JK Enthusiast
Joined: Jul 2010
Posts: 201
Likes: 1
From: Northern, NJ
After a few days of driving the CEL went off and has not returned. As I previously stated the Jeep has been running fine. I'm gonna leave everything alone and see if the CEL/code returns.
Thanks to everyone who gave me their input.
Thanks to everyone who gave me their input.
JK Newbie
Joined: Sep 2013
Posts: 28
Likes: 0
From: Victorville, CA
Update
Any updates on this issue? I’m at 138k on my 09 and just replaced all sensors and gas cap after P0420 code. CEL still comes on with that code. Drives fine.
I have a tuner set to performance and run 91 octane. Could this be the issue?
I have a tuner set to performance and run 91 octane. Could this be the issue?
