Code No. P0421: Catalyst Malfunction




FUNCTION




TROUBLE JUDGEMENT


Check Conditions
Judgement Criterion
note The specified value varies depending on the average air flow rate.

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Replace the catalytic converter.



  • After replacing the catalytic converter, reconfirm whether the diagnosis code is stored.

Q. Is the diagnosis code stored?

Replace the engine-ECU.
Check end.