Causes and fixes of a P0420 Code: Catalyst System Efficiency Below Threshold (Bank 1)
A P0420 code is set when the computer (ECM/PCM) detects that the Bank-1 catalytic converter has falling below 92% efficiency.
The catalytic converter is monitored by two O2 sensors located on the exhaust.
If the catalytic converter is the issue cleaner can be used that can sometimes give it more mileage (results vary).
Amazon Link Infrared Thermometer: [ Ссылка ]
How To Test a Catalytic Converter with Infrared Thermometer Video
[ Ссылка ]
Possible Causes of a P0420 Code:
Bad Oxygen Sensor or Wiring
Bad Catalytic Converter
Exhaust Leak
Engine problem (Injector leak / High Fuel Pressure)
By using this information, the user assumes all risks of use.
