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Home › Nissan-Datsun › 2012 › Quest SL › Repair and Diagnosis › Engine Performance › System › Engine Control System - Introduction › DTC/Circuit Diagnosis › Power Supply And Ground Circuit › Diagnosis Procedure

Diagnosis Procedure

  1. CHECK FUSE

    Check that the following fuse is not fusing.

    Location Fuse No. Capacity
    IPDM E/R #44 10 A
    #50 15 A

    Is the fuse fusing? 

    YES: Replace the fuse after repairing the applicable circuit.

    NO: GO TO 2.

  2. CHECK GROUND CONNECTION
    1. Turn ignition switch OFF.
    2. Check ground connection E38. Refer to "CIRCUIT INSPECTION ".

      Is the inspection result normal? 

      YES: GO TO 3.

      NO: Repair or replace ground connection.

  3. CHECK ECM GROUND CIRCUIT
    1. Disconnect ECM harness connectors.
    2. Check the continuity between ECM harness connector and ground.
      + - Continuity
      ECM
      Connector Terminal
      F7 16 Ground Existed
      12
      E16 123
      124
      127
      128

      Is the inspection result normal? 

      YES: GO TO 4.

      NO: Repair or replace error-detected parts.

  4. CHECK ECM POWER SUPPLY (MAIN)-I
    1. Reconnect ECM harness connector.
    2. Turn ignition switch ON.
    3. Check the voltage between ECM harness connector terminals.
      ECM Voltage
      Connector + -
      Terminal
      E16 121 128 Battery voltage

      Is the inspection result normal? 

      YES: GO TO 5.

      NO: GO TO  6.

  5. CHECK ECM POWER SUPPLY (MAIN)-II
    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Check the voltage between ECM harness connector terminals as per the following.
      ECM Condition Voltage (Approx.)
      Connector + -
      Terminal
      E16 121 128 After turning ignition switch OFF, battery voltage will exist for a few seconds Drop to 0 V

      Is the inspection result normal? 

      YES: GO TO  9.

      NO: GO TO  7.

  6. CHECK ECM POWER SUPPLY (MAIN) CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connectors.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between ECM harness connector and IPDM E/R harness connector.
      + - Continuity
      ECM IPDM E/R
      Connector Terminal Connector Terminal
      E16 121 E10 10 Existed
    5. Also check harness for short to ground.

      Is the inspection result normal? 

      YES: Perform the trouble diagnosis for power supply circuit.

      NO: Repair or replace error-detected parts.

  7. CHECK ECM RELAY CONTROL SIGNAL

    Check the voltage between ECM harness connector terminals as per the following.

    ECM Condition Voltage (Approx.)
    + -
    Connector Terminal Connector Terminal
    F7 31 E16 128 Ignition switch ON 0 V
    Turn ignition switch OFF and wait at least 10 seconds. Battery voltage

    Is the inspection result normal? 

    YES: Check intermittent incident. Refer to "INTERMITTENT INCIDENT ".

    NO: GO TO 8.

  8. CHECK ECM RELAY CONTROL SIGNAL CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between ECM harness connector and IPDM E/R harness connector.
      + - Continuity
      ECM IPDM E/R
      Connector Terminal Connector Terminal
      F7 31 F12 69 Existed
    5. Also check harness for short to ground and to power.

      Is the inspection result normal? 

      YES: Replace IPDM E/R. Refer to "REMOVAL AND INSTALLATION ".

      NO: Repair or replace error-detected parts.

  9. CHECK IGNITION SWITCH SIGNAL
    1. Turn ignition switch ON.
    2. Check the voltage between ECM harness connector terminals.
      ECM Condition Voltage (Approx.)
      Connector + -
      Terminal
      E16 109 128 Ignition switch OFF 0 V
      Ignition switch ON Battery voltage

      Is the inspection result normal? 

      YES: GO TO  11.

      NO: GO TO 10.

  10. CHECK IGNITION SWITCH SIGNAL CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between ECM harness connector and IPDM E/R harness connector.
      + - Continuity
      ECM IPDM E/R
      Connector Terminal Connector Terminal
      E16 109 E10 19 Existed
    5. Also check harness for short to ground and to power.

      Is the inspection result normal? 

      YES: Perform the trouble diagnosis for power supply circuit.

      NO: Repair or replace error-detected parts.

  11. CHECK ECM POWER SUPPLY (BACK-UP)

    Check the voltage between ECM harness connector terminals.

    ECM Voltage
    + -
    Connector Terminal Connector Terminal
    F7 26 E16 128 Battery voltage

    Is the inspection result normal? 

    YES: Check intermittent incident. Refer to "INTERMITTENT INCIDENT ".

    NO: GO TO 12.

  12. CHECK ECM POWER SUPPLY (BACK-UP) CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between ECM harness connector and IPDM E/R harness connector.
      + - Continuity
      ECM IPDM E/R
      Connector Terminal Connector Terminal
      F7 26 F12 55 Existed
    5. Also check harness for short to ground.

      YES: Perform the trouble diagnosis for power supply circuit.

      NO: Repair or replace error-detected parts.

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