Need help with P0420 code. Read the other post no help!
Thread Starter
Heel & Toe
Joined: Sep 2005
Posts: 22
Likes: 0
Need help with P0420 code. Read the other post no help!
OK I have been getting the P0420 code and have been clearing it, but it comes back every 300 miles or so. I turned off my rear o2 sensors with my programmer and it still comes back on. Last time I also got the p0430 code as well. I cleaned my MAF the other day with contact cleaner like recommended and now the check engine light came on only after about 100 miles. It was just the p0420 again and with the back o2 sensors off. Any ideas? The car runs good and strong. I did notice a couple times when sitting idling the tack moves a little and it does sound like it runs a hair ruff but only on occasion. Any ideas? It's an 07 C6
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
This sounds simple but when turning off the rear 02s did you also check the box to so that it doesn't report the failure? In HP Tuners, if I remember, there are 3 boxes to check when turning off the rear 02s.
420 is bank 1
420 is bank 1
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
In HP Tuners you can turn them off but you also have to select a box to turn off the reporting or it will still set the light. I don't know what all the predator does.
