CR-V LX 2WD L4-1972cc 2.0L DOHC MFI (1998)
Three Way Catalytic (TWC) Converter: Testing and Inspection
[P0420]
The scan tool indicates Diagnostic Trouble Code (DTC) P0420: Catalyst system efficiency below threshold
Description
This system evaluates the catalyst's capacity by means of the HO2S (Primary and Secondary) output during stable driving conditions. If deterioration
has been detected during three consecutive driving cycles, the MIL comes on and DTC P0420 will be stored.
NOTE: If some of the DTCs listed below are stored at the same time as DTC P0420, troubleshoot those DTCs first, then troubleshoot DTC P0420.
P0137, P0138: Secondary H025 (Sensor 2)
P0141: Secondary HO2S (Sensor 2) Heater
Possible Cause
-
TWC Deterioration
-
Exhaust system leakage
