Trouble code
08-30-2018, 06:34 AM
#2
Moderator, Tech Contributor
Member Since: Sep 2013
Location: Cape Coral, Florida
Posts: 9,517
Received 2,122 Likes
on
1,687 Posts
P0420 is Cat efficiency below normal on Bank 1...do you have a scan tool that can graph your O2 sensor signals ??...will help immensely in the diagnosis !!
08-31-2018, 01:56 PM
#3
08-31-2018, 04:45 PM
#4
Moderator, Tech Contributor
Member Since: Sep 2013
Location: Cape Coral, Florida
Posts: 9,517
Received 2,122 Likes
on
1,687 Posts
09-02-2018, 08:11 PM
#5
Le Mans Master
Member Since: Aug 2005
Location: CA.
Posts: 5,255
Likes: 0
Received 281 Likes
on
258 Posts
St. Jude Donor '13-'14-'15
Do you have headers on your car ????? If you have LT headers this is a common issue and most likely will never go away Best way is to have a tuner DELETE all the REAR 02 reporting and codes permanently
PS The front 02's are very important as they take readings ane by those readings the ECM makes adjustmets to your AFR at P/T to achive the STOICH fuel ratio of 14.68-1
HOWEVER the rear 02,s are only there to "report the condition of your CATS" and have no affect on fueling at P/T ( unless the cats are plugged up) Before spending what can be $1000 on new cats I would take your car to your local muffler shop and they have a tool that can measure the restriction in your cats to see if they are plugged If they are --You need new ones---If they are NOT then most likely it is what they call a "fasle code" from lazy rear 02's Then you can either change them or have a tuner delete the cat codes forever !
PS The front 02's are very important as they take readings ane by those readings the ECM makes adjustmets to your AFR at P/T to achive the STOICH fuel ratio of 14.68-1
HOWEVER the rear 02,s are only there to "report the condition of your CATS" and have no affect on fueling at P/T ( unless the cats are plugged up) Before spending what can be $1000 on new cats I would take your car to your local muffler shop and they have a tool that can measure the restriction in your cats to see if they are plugged If they are --You need new ones---If they are NOT then most likely it is what they call a "fasle code" from lazy rear 02's Then you can either change them or have a tuner delete the cat codes forever !
Last edited by tblu92; 09-04-2018 at 04:58 PM.
09-02-2018, 08:49 PM
#6
Moderator, Tech Contributor
Member Since: Sep 2013
Location: Cape Coral, Florida
Posts: 9,517
Received 2,122 Likes
on
1,687 Posts
Do you have headers on your cae ????? If you have LT headers this is a common issye and most like;y will never go away Best way is to have a tuner DELETE all the REAR 02 reporting and codes permanently
PS The front 02's are very important as they take readings ane by those readings the ECM makes adjustmets to your AFR at P/T to achive the STOICH fuel ratio of 14.68-1
HOWEVER the rear 02,s are only there to "report the condition of your CATS and have no affect on fueling at P/T ( unless the cats are plugged up) Before spending what can be $1000 on new cats I would take your car to your local muffler shop and they have a tool that can measure the restriction in your cats to see if they are plugged If they are --You need new ones---If they are NOT then most likely it is what they call a "fasle code" from lazy rear 02's Then you can either change them or have a tuner delete the cat codes forever !
PS The front 02's are very important as they take readings ane by those readings the ECM makes adjustmets to your AFR at P/T to achive the STOICH fuel ratio of 14.68-1
HOWEVER the rear 02,s are only there to "report the condition of your CATS and have no affect on fueling at P/T ( unless the cats are plugged up) Before spending what can be $1000 on new cats I would take your car to your local muffler shop and they have a tool that can measure the restriction in your cats to see if they are plugged If they are --You need new ones---If they are NOT then most likely it is what they call a "fasle code" from lazy rear 02's Then you can either change them or have a tuner delete the cat codes forever !