header causing o2 problems
Thread Starter
Advanced
Joined: May 2003
Posts: 62
Likes: 1
From: dillsburg pa
header causing o2 problems
I just installed long tube LG headers with cats. I'm getting code PO420HC. My 4 o2 sensers are installed correctly. I live near Harrisburg Pa. and we have emission testing. I would like to have all 4 o2 sensers working if possible and not put o2 simulators on the back 2. what are my options ? How do I clear the code or code history.
Racer
Joined: Dec 2005
Posts: 270
Likes: 1
From: Springfield OH
With ignition on and engine not running, push and hold the options button. Now push the fuel button four times to enter diagnostic mode. Push options button again to enter manual diagnostic mode. Push trip button to move back and options button to move forward through the diagnostics. When you have codes and want to erase them, hold the reset button until the "no codes" is displayed. To exit the manual diagnotics, push e/m button.
Since you now have headers, a tune most likely can get ride of the 0420.
Since you now have headers, a tune most likely can get ride of the 0420.
Last edited by TorchRed00FRC; Mar 31, 2007 at 07:53 AM.
Drifting
Joined: Oct 2003
Posts: 1,540
Likes: 0
From: bloomfield nj
I just installed long tube LG headers with cats. I'm getting code PO420HC. My 4 o2 sensers are installed correctly. I live near Harrisburg Pa. and we have emission testing. I would like to have all 4 o2 sensers working if possible and not put o2 simulators on the back 2. what are my options ? How do I clear the code or code history.
Instructor
Joined: Mar 2006
Posts: 153
Likes: 0
From: chicago il
PO420 is not a o2 sensor problem.it's low flow secondary air on bank 1[left side].are the hoses all hooked back up correctly? is the check valve base tight and gasket good[if not you may end up with a bank 1 lean fault also]? check the hose that comes off the left side check valve that goes to the "t" on the left side from the pump to make sure it's not pinched/off/cut/etc.
this may not be incorrect 100% of the time, p420 is cat inefficient, which is very common with hi flow cats or no cats at all. a tune or o2 sims will clear this up. i used sims to clear up my p420 & p430.
