Need help with code P0420
Thread Starter
Teching In
Joined: Dec 2002
Posts: 22
Likes: 0
From: Canada
Need help with code P0420 Had TPiS headers, y-pipe, and cats installed way back in November. Everything went fine.
Last week had a horrible rattle from underneath the car. By the time I had it looked at two days later the rattle disappeared completely. Couldn't visibly see anything that fell off the car. Car ran fine.
Two days later while driving. Filled up with regular gas (belowing freezing temps here and not going full throttle anytime soon). Car throws a code - P0420 (smoke 'em if ya got 'em). No loss in performance nor can I tell anything is out of the ordinary.
We reset the code last night. After driving for about 60 miles today the code came back on. The car is using O2 extenders.
This car also needs to pass emissions in a few weeks.
So LS1Tech Gods, please help me!
Last week had a horrible rattle from underneath the car. By the time I had it looked at two days later the rattle disappeared completely. Couldn't visibly see anything that fell off the car. Car ran fine.
Two days later while driving. Filled up with regular gas (belowing freezing temps here and not going full throttle anytime soon). Car throws a code - P0420 (smoke 'em if ya got 'em). No loss in performance nor can I tell anything is out of the ordinary.
We reset the code last night. After driving for about 60 miles today the code came back on. The car is using O2 extenders.
This car also needs to pass emissions in a few weeks.
So LS1Tech Gods, please help me!
That code is the Air Injection Malfunction code if I'm not mistaken. No biggie... What set mine off first was when I installed my catback. It had nothing to do with that really. It just means the AIR system is working correctly, or not getting enough air in order to work correctly.
What fixed mine was moving the filter that I installed on the AIR hose from when I installed the aftermarket lid.
You can either rip out the system, or just delete the code. Like I said, just try moving the AIR hose first to a different spot. It's useful with high flow cats, just so you dont burn up an expensive cat...
It shouldn't affect your emissions testing, depending upon how they do it in your state.
Rob
What fixed mine was moving the filter that I installed on the AIR hose from when I installed the aftermarket lid.
You can either rip out the system, or just delete the code. Like I said, just try moving the AIR hose first to a different spot. It's useful with high flow cats, just so you dont burn up an expensive cat...
It shouldn't affect your emissions testing, depending upon how they do it in your state.
Rob
TECH Resident
Joined: Jul 2003
Posts: 834
Likes: 0
From: Marysville, OH
P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
Unless you have "code" checking with your emisions testing I think you will be fine. If you do have code checking you might want to buy O2 simms if your code keeps coming back.
Unless you have "code" checking with your emisions testing I think you will be fine. If you do have code checking you might want to buy O2 simms if your code keeps coming back.
