LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2021 >> Q60 Pure, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (4 Of 7) >> Engine (ECM) >> DTC P0430: Three Way Catalyst Function >> DTC Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC Diagnosis Procedure

  1. CHECK EXHAUST SYSTEM 

    Visually check exhaust tubes and muffler for dents.

    Is the inspection result normal?

    YES

    GO TO 2.

    NO

    Repair or replace.

  2. CHECK EXHAUST GAS LEAK 
    1. Start engine and run it at idle.
    2. Listen for an exhaust gas leak before the three way catalyst 1.
      G04073923Courtesy of NISSAN NORTH AMERICA, INC.

    Is exhaust gas leak detected?

    YES

    Repair or replace.

    NO

    GO TO 3.

  3. CHECK INTAKE AIR LEAK 

    Listen for an intake air leak after the mass air flow sensor.

    Is intake air leak detected?

    YES

    Repair or replace.

    NO

    GO TO 4.

  4. CHECK IDLE SPEED AND IGNITION TIMING 

    For procedure, Refer to Work Procedure .

    For specification, Refer to IDLE SPEED : Service Data . and Refer to IGNITION TIMING : Service Data .

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Follow the Refer to Work Procedure .

  5. CHECK FUEL INJECTORS 

    Check the fuel injector. Refer to Component Function Check .

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Refer to Diagnosis Procedure .

  6. CHECK FUNCTION OF IGNITION COIL-I 
    CAUTION: Perform the following procedure in a place where with no combustible objects and good ventilation.
    1. Turn ignition switch OFF.
    2. Pull out 15A fuse (No. 52) from IPDM E/R to release fuel pressure. Refer to Wiring Diagram .
      NOTE: Do not use CONSULT to release fuel pressure, or fuel pressure applies again during the following procedure.
    3. Start engine.
    4. After engine stalls, crank it two or three times to release all fuel pressure.
    5. Turn ignition switch OFF.
    6. Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
    7. Remove ignition coil and spark plug of the cylinder to be checked.
    8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
    9. Connect spark plug and harness connector to ignition coil.
    10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal portion as shown in the figure.
      G04886523Courtesy of NISSAN NORTH AMERICA, INC.
    11. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal portion.

      Spark should be generated.

      CAUTION:
      • Never place the spark plug and the ignition coil within 50 cm (19.7 in) each other. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.
      • It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
      NOTE: When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunctioning.

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    GO TO 7.

  7. CHECK FUNCTION OF IGNITION COIL-II 
    1. Turn ignition switch OFF.
    2. Disconnect spark plug and connect a non-malfunctioning spark plug.
    3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.

      Spark should be generated.

    Is the inspection result normal?

    YES

    GO TO 8.

    NO

    Check ignition coil, power transistor and their circuits. Refer to Diagnosis Procedure .

  8. CHECK SPARK PLUG 

    Check the initial spark plug for fouling, etc.

    G04185314Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES

    Replace spark plug(s) with standard type one(s). For spark plug type, Refer to SPARK PLUG : Service Data .

    NO

    Repair or clean spark plug. Then GO TO 9.

  9. CHECK FUNCTION OF IGNITION COIL-III 
    1. Reconnect the initial spark plugs.
    2. Crank engine for about three seconds, and recheck whether spark is generated between the spark plug and the grounded portion.

      Spark should be generated.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Replace spark plug(s) with standard type one(s). For spark plug type, Refer to SPARK PLUG : Service Data .

  10. PERFORM DTC CONFIRMATION PROCEDURE 
    1. Replace three way catalyst. Refer to CATALYST : Removal & Installation .
    2. Perform DTC confirmation procedure. Refer to DTC Description .

    Is DTC P0430 detected?

    YES

    Replace all fuel injector. Refer to FUEL INJECTOR AND FUEL TUBE : Removal & Installation .

    NO

    INSPECTION END