Need a little help. P0420
This is a discussion on Need a little help. P0420 within the General Help forums, part of the LSx Technical Help Section category; Originally Posted by Mustang=Breakfast Bad 02 sensors can give faulty codes like that... That is true. On my dads chevy ...
07-09-2008, 04:25 PM #21
07-09-2008, 04:25 PM #22
A code P0420 may mean that one or more of the following has happened:
Leaded fuel was used where unleaded was called for
An oxygen sensor is not reading (functioning) properly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Some suggested steps for troubleshooting a P0420 code include:
Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
Inspect the downstream heated oxygen sensor (HO2), replace if necessary
Replace the catalytic converter
07-09-2008, 04:47 PM #23
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By Thorinman in forum Computer & TuningReplies: 3Last Post: 04-14-2008, 06:00 AM
By VTR99 in forum External EngineReplies: 11Last Post: 09-12-2007, 03:08 PM
By BigKid in forum External EngineReplies: 3Last Post: 06-27-2006, 09:36 AM
By z28rktec in forum General HelpReplies: 1Last Post: 01-21-2006, 10:51 AM
By delinquent543 in forum Computer & TuningReplies: 8Last Post: 12-28-2005, 08:16 AM