Code help P420 and P430
Thread Starter
Race Director
Joined: Sep 2004
Posts: 17,786
Likes: 4
From: Redsox, Pats, Celts & Bruins !!! Redsox Nation !!!
St. Jude Donor '06-'07-'08-'09-'10-'11-'12
Code help P420 and P430
Catalyst efficiency below threshold bank 1
Catalyst efficiency below threshold bank 2
Both came up would it be the CAT of the O2s?
Thanks
Catalyst efficiency below threshold bank 2
Both came up would it be the CAT of the O2s?
Thanks
Racer
Joined: Jul 2006
Posts: 285
Likes: 1
From: Placentia CA
Generally a 420/430 means the PCM is seeing too much activity on the rear O2s. If the cats are warmed up and working properly the rear O2s should be “flat lined” at a very low voltage. Like .1 to .3 with very little up and down movement. So…. If the cats are being properly feed the right amount of CO and O2 (no other codes) …….It’s the cats! Several ways to deal with this.
1. Install cats the PCM is happy with.
2. Make the PCM happy with the cats you have.
3. Tell the PCM to forget we have cats and rear O2 sensors.
Of course what you do will depend on your ability to tune/edit the PCM and weather you have to worry about a smog test. And as always this is JMHO.
1. Install cats the PCM is happy with.
2. Make the PCM happy with the cats you have.
3. Tell the PCM to forget we have cats and rear O2 sensors.
Of course what you do will depend on your ability to tune/edit the PCM and weather you have to worry about a smog test. And as always this is JMHO.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
If it is the cats, one thing to note, a lot of guys are more than willing to unload their stock H pipe for very cheap or sometimes free. I would imagine they are expensive from GM. Mine is hanging on my ceiling in the basement 
