Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Infiniti >> 2008 >> G37 Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - G37 Coupe - Introduction >> Component Diagnosis >> Power Supply And Ground Circuit >> Diagnosis Procedure

Diagnosis Procedure

  1. INSPECTION START

    Start engine.

    Is engine running? 

    YES: GO TO  8.

    NO: GO TO 2.

  2. CHECK ECM POWER SUPPLY CIRCUIT-I
    1. Turn ignition switch OFF and then ON.
    2. Check the voltage between ECM harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      ECM Ground Voltage
      Connector Terminal
      F102 53 Ground Battery voltage

    Is the inspection result normal? 

    YES: GO TO  4.

    NO: GO TO 3.

  3. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E3, F1
    • IPDM E/R harness connector E7
    • 10A fuse (No. 44)
    • Harness for open or short between ECM and fuse

      Repair open circuit or short to ground or short to power in harness or connectors.

  4. CHECK GROUND CONNECTION-I
    1. Turn ignition switch OFF.
    2. Check ground connection M95. Refer to Ground Inspection in "CIRCUIT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO 5.

    NO: Repair or replace ground connection.

  5. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
    1. Disconnect ECM harness connector.
    2. Check the continuity between ECM harness connector and ground.
      TERMINALS CONTINUITY REFERENCE

      ECM Ground Continuity
      Connector Terminal
      F101 8 Ground Existed
      M107 123
      124
      127
      128
    3. Also check harness for short to power.

    Is the inspection result normal? 

    YES: GO TO  7.

    NO: GO TO 6.

  6. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors F103, M116
    • Harness for open or short between ECM and ground

      Repair open circuit or short to power in harness or connectors.

  7. CHECK ECM POWER SUPPLY CIRCUIT-II
    1. Reconnect ECM harness connector.
    2. Turn ignition switch ON.
    3. Check the voltage between IPDM E/R harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      IPDM E/R Ground Voltage
      Connector Terminal
      E7 53 Ground Battery voltage

    Is the inspection result normal? 

    YES: Go to "DIAGNOSIS PROCEDURE ".

    NO: GO TO 8.

  8. CHECK ECM POWER SUPPLY CIRCUIT-III
    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Check the voltage between ECM harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      ECM Ground Voltage
      Connector Terminal
      M107 125 Ground After turning ignition switch OFF, battery voltage will exist for a few seconds, then drop approximately 0V.

    Is the inspection result normal? 

    YES: GO TO  15.

    NO-1: Battery voltage does not exist: GO TO 9.

    NO-2: Battery voltage exists for more than a few seconds: GO TO  12.

  9. CHECK ECM POWER SUPPLY CIRCUIT-IV
    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Check the voltage between ECM harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      ECM Ground Voltage
      Connector Terminal
      F101 24 Ground Battery voltage

    Is the inspection result normal? 

    YES: GO TO 10.

    NO: GO TO  12.

  10. CHECK ECM POWER SUPPLY CIRCUIT-V
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E7.
    3. Check the continuity between ECM harness connector and IPDM E/R harness connector.
      TERMINALS CONTINUITY REFERENCE

      ECM IPDM E/R Continuity
      Connector Terminal Connector Terminal
      M107 125 E7 49 Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  18.

    NO: GO TO 11.

  11. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness or connectors E106, M6
    • Harness for open or short between ECM and IPDM E/R

      Repair open circuit or short to ground or short to power in harness or connectors.

  12. CHECK ECM POWER SUPPLY CIRCUIT-VI
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E7.
    3. Check the continuity between ECM harness connector and IPDM E/R harness connector.
      TERMINALS CONTINUITY REFERENCE

      ECM IPDM E/R Continuity
      Connector Terminal Connector Terminal
      F101 24 E7 69 Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO step 14 in DIAGNOSIS PROCEDURE .

    NO: GO TO 13.

  13. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness or connectors E3, F1
    • Harness connectors F104, F105
    • Harness for open or short between ECM and IPDM E/R

      Repair open circuit or short to ground or short to power in harness or connectors.

  14. CHECK 15A FUSE
    1. Disconnect 15A fuse (No. 50) from IPDM E/R.
    2. Check 15A fuse.

    Is the inspection result normal? 

    YES: GO TO  18.

    NO: Replace 15A fuse.

  15. CHECK GROUND CONNECTION-II

    Check ground connection M95. Refer to Ground Inspection in "CIRCUIT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO 16.

    NO: Repair or replace ground connection.

  16. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II
    1. Disconnect ECM harness connector.
    2. Check the continuity between ECM harness connector and ground.
      TERMINALS CONTINUITY REFERENCE

      ECM Ground Continuity
      Connector Terminal
      F101 8 Ground Existed
      M107 123
      124
      127
      128
    3. Also check harness for short to power.

    Is the inspection result normal? 

    YES: GO TO  18.

    NO: GO TO 17.

  17. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness or connectors F103, M116
    • Harness for open or short between ECM and ground

      Repair open circuit or short to power in harness or connectors.

  18. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    Is the inspection result normal? 

    YES: Replace IPDM E/R.

    NO: Repair open circuit or short to ground or short to power in harness or connectors.

scientia non olet · About Mike's Workshop Manuals