P0420 ISUZU – Catalyst System Low Efficiency Bank 1

 

P0420: DIY Repairing Video Tutorial

www.youtu.be/1y190iiOtDM

Check out nonda Auto DIY Center for more engine error code repairing videos.
https://www.youtube.com/playlist?list=PL-Lyko0O0oxHe1AGvzwAz-wokJPXAtW97

 

P0420 ISUZU Possible Symptoms

  Engine Light ON (or Service Engine Soon Warning Light)  

P0420 ISUZU Possible Causes

  Faulty Three-way Catalyst Converter Bank 1,Exhaust Tube,Intake Air Leaks,Faulty Oxygen (O2) Sensor,Faulty Fuel injector(s),Leaking Fuel Injector (s),Faulty Spark plugs,Improper Ignition Timing,Faulty Engine Control Module (ECM),Dirty Air Filter  

P0420 ISUZU Description

  The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor). A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase. When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.