Code No. P0420: Catalyst Malfunction




FUNCTION




TROUBLE JUDGMENT


Check Condition
Judgement Criteria

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III data list.



  • Refer to Data List Reference Table .

  1. Item 117: No. 1 exhaust gas temperature sensor
  2. Item 118: No. 2 exhaust gas temperature sensor (catalyst temperature)

Q. Are the check results normal?

Go to Step 2.
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 2. Forcible DPF regeneration execution



  • Initialise the DPF-related parts, and then erase the diagnosis code (Refer to GROUP 00 - Precautions before Service - Initialisation Procedure for Learning Value in Common Rail Engine <4N1> ).

  1. Item 42: DPF system malfunction service
  • Carry out the forcible DPF regeneration (Refer to GROUP 17 - Emission Control <DIESEL> - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
  • Q. Is the diagnosis code P0420 or P2458 set?

    Replace the catalytic converter. When the catalytic converter is replaced, initialise the learning value. (Refer to GROUP 00 - Precautions before Service - Initialisation Procedure for Learning Value in Common Rail Engine <4N1> ). On completion, carry out the forcible DPF regeneration (Refer to GROUP 17 - Emission Control <DIESEL> - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
    Replace the engine-ECU.