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Home >> Nissan-Datsun >> 2004 >> Altima S, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1179 (Engine Control System - DTCS P0181 To P0550 (VK56DE)) >> DTC P0420, P0430: Three Way Catalyst Function >> Diagnosis Procedure

Diagnosis Procedure

WARNING: This page is about a different car, the 2012 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK EXHAUST SYSTEM

    Visually check exhaust tubes and muffler for dents.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace malfunctioning part.

  2. CHECK EXHAUST GAS LEAKAGE
    1. Start engine and run it at idle.
    2. Listen for an exhaust gas leakage before the three way catalyst (manifold).
    Fig 1: Checking Exhaust Gas Leak
    G08165037Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 3.

    NG: Repair or replace malfunctioning part.

  3. CHECK INTAKE AIR LEAKAGE

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

    OK or NG 

    OK: GO TO 4.

    NG: Repair or replace malfunctioning part.

  4. CHECK IGNITION TIMING

    Check the following items. Refer to "BASIC INSPECTION ".

    Items Specifications
    Idle speed 650 ± 50 RPM (in P or N position)
    Ignition timing 15 ± 5° BTDC (in P or N position)

    OK or NG 

    OK: GO TO 5.

    NG: Follow the instructions on "BASIC INSPECTION ".

  5. CHECK FUEL INJECTOR
    1. Stop engine and then turn ignition switch ON.
    2. Check voltage between ECM terminals 21, 22, 23, 40, 41, 42, 44, 63 and ground with CONSULT or tester.

    Battery voltage should exist  .

    OK or NG 

    OK: GO TO 6.

    NG: Perform "DIAGNOSIS PROCEDURE ".

    Fig 2: Checking Voltage Between ECM Terminals 21, 22, 23, 40, 41, 42, 44, 63 And Ground Using Tester
    G08165038Courtesy of NISSAN NORTH AMERICA, INC.
  6. CHECK FUNCTION OF IGNITION COIL-I
    CAUTION: Never following procedure in a place with no combustible objects and good ventilation.
    1. Turn ignition switch OFF.
    2. Remove fuel pump fuse (1) in IPDM E/R (2) to release fuel pressure.
      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 2 or 3 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.
      Fig 3: Identifying Fuel Pump Fuse And IPDM E/R
      G08165039Courtesy of NISSAN NORTH AMERICA, INC.
    7. Remove ignition coil and spark plug of the cylinder to be checked. Refer to IGNITION COIL .
    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 between the edge of the spark plug and grounded metal portion as shown in the figure.
    11. Crank engine for approximately 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 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 is made.
    Fig 4: Identifying Spark Length Between Edge Of Spark Plug And Grounded Metal Portion
    G08165040Courtesy of NISSAN NORTH AMERICA, INC.
    NOTE: When the gap is less than 13 mm, a spark might be generated even if the coil is malfunctioning.

    OK or NG 

    OK: GO TO  10.

    NG: 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 approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.

    Spark should be generated  .

    OK or NG 

    OK: GO TO 8.

    NG: Check ignition coil, power transistor and their circuits. Refer to "DIAGNOSIS PROCEDURE ".

  8. CHECK SPARK PLUG

    Check the initial spark plug for fouling, etc.

    OK or NG 

    OK: Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to "STANDARD AND LIMIT ".

    NG >>

    1. Repair or clean spark plug. Refer to IGNITION COIL .
    2. GO TO 9.
    Fig 5: Identifying Initial Spark Plug
    G08165041Courtesy of NISSAN NORTH AMERICA, INC.
  9. CHECK FUNCTION OF IGNITION COIL-III
    1. Reconnect the initial spark plugs.
    2. Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.

    Spark should be generated  .

    OK or NG 

    OK: INSPECTION END 

    NG: Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to "STANDARD AND LIMIT ".

  10. CHECK FUEL INJECTOR
    1. Turn ignition switch OFF.
    2. Remove fuel injector assembly. Refer to "REMOVAL AND INSTALLATION ".

      Keep fuel hose and all fuel injectors connected to fuel injector gallery.

    3. Disconnect all ignition coil harness connectors.
    4. Reconnect all fuel injector harness connector disconnected.
    5. Turn ignition switch ON.

    Make sure fuel does not drip from fuel injector.

    OK or NG 

    OK (Does not drip.)>>GO TO 11.

    NG (Drips.)>>Replace the fuel injector(s) from which fuel is dripping. Refer to FUEL INJECTOR AND FUEL TUBE .

  11. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    Trouble is fixed.>>INSPECTION END 

    Trouble is not fixed.>>Replace malfunctioning three way catalyst assembly. Refer to EXHAUST MANIFOLD AND THREE WAY CATALYST .

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