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Home >> Nissan-Datsun >> 2021 >> NV2500 HD S >> Repair and Diagnosis >> External Pages >> Different car >> Section 617 (Engine Control System (DTC/Circuit Diagnosis) (1 Of 17)) >> DTC/Circuit Diagnosis >> Power Supply And Ground Circuit >> Diagnosis Procedure

Diagnosis Procedure

WARNING: This page is about a different car, the 2020 Infiniti QX60. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FUSE 
    1. Turn ignition switch OFF.
    2. Check that the following fuse is not blowing.

      Location

      Fuse No.

      Capacity

      IPDM E/R

      #39

      10A

      #45

      10A

      #56

      10A

    Is the fuse blown (open)?

    YES

    Replace the fuse after repairing the applicable circuit.

    NO

    GO TO 2.

  2. CHECK GROUND CONNECTION 

    Check ground connection E9. Refer to Ground Inspection in Circuit Inspection .

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Repair or replace error-detected parts.

  3. CHECK ECM GROUND CIRCUIT 
    1. Disconnect ECM harness connectors.
    2. Check the continuity between ECM harness connector and ground.

      ECM

      --

      Continuity

      Connector

      Terminal

      F78

      2

      Ground

      Existed

      7

      F79

      87

      88

      95

      E32

      199

      201

      204
    3. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Repair or replace error-detected parts.

  4. CHECK IGNITION SWITCH SIGNAL 

    Check the voltage between ECM harness connectors as follows.

    ECM

    Condition

    Voltage

    Connector

    +

    -

    Terminal

    E32

    185

    204

    Ignition switch: ON

    Battery voltage

    Ignition switch: OFF

    0 V

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    GO TO 5.

  5. CHECK IGNITION SWITCH SIGNAL CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connectors.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between IPDM E/R harness connector and ECM harness connector.

      IPDM E/R

      ECM

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      E119

      21

      E32

      185

      Existed
    5. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    Perform trouble diagnosis for power supply circuit.

    NO

    Repair or replace error-detected parts.

  6. CHECK ECM POWER SUPPLY 
    1. Reconnect ECM harness connectors.
    2. Check the voltage between ECM harness connector terminals as follows.

      ECM

      Condition

      Voltage

      Connector

      +

      -

      Terminal

      E32

      197

      204

      Ignition switch: ON

      Battery voltage
      • Ignition switch: OFF
      • More than a few seconds after turning ignition switch OFF

      0 V

    Is the inspection result normal?

    YES

    GO TO 11.

    NO

    GO TO 7.

  7. CHECK ECM POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connectors.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between IPDM E/R harness connector and ECM harness connector.

      IPDM E/R

      ECM

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      F19

      59

      E32

      197

      Existed
    5. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    GO TO 8.

    NO

    Repair or replace error-detected parts.

  8. CHECK ECM RELAY CONTROL SIGNAL 
    1. Reconnect ECM harness connectors.
    2. Reconnect IPDM E/R harness connectors.
    3. Turn ignition switch ON.
    4. Turn ignition switch OFF and wait at least 10 seconds.
    5. Check the voltage between ECM harness connectors as follows.

      ECM

      Condition

      Voltage

      +

      -

      Connector

      Terminal

      Connector

      Terminal

      F79

      125

      E32

      204
      • Ignition switch: OFF
      • A few seconds after turning ignition switch OFF

      0 - 1.0 V
      • Ignition switch: OFF
      • More than a few seconds after turning ignition switch OFF

      Battery voltage

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    GO TO 9.

  9. CHECK ECM RELAY CONTROL SIGNAL CIRCUIT 
    1. Disconnect ECM harness connectors.
    2. Disconnect IPDM E/R harness connector.
    3. Check the continuity between IPDM E/R harness connector and ECM harness connector.

      IPDM E/R

      ECM

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      F24

      72

      F79

      125

      Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    Repair or replace error-detected parts.

  10. CHECK POWER SUPPLY CIRCUIT 

    Perform trouble diagnosis for power supply circuit.

    Is the inspection result normal?

    YES

    Replace IPDM E/R. Refer to Removal and Installation .

    NO

    Repair or replace error-detected parts.

  11. CHECK ECM POWER SUPPLY (BACK-UP) 
    1. Turn ignition switch OFF.
    2. Check the voltage between ECM harness connectors as follows.

      ECM

      Condition

      Voltage

      +

      -

      Connector

      Terminal

      Connector

      Terminal

      F79

      170

      E32

      204

      Ignition switch: OFF

      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. Disconnect ECM harness connectors.
    2. Disconnect IPDM E/R harness connector.
    3. Check the continuity between IPDM E/R harness connector and ECM harness connector.

      IPDM E/R

      ECM

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      F19

      58

      F79

      170

      Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    Perform trouble diagnosis for power supply circuit.

    NO

    Repair or replace error-detected parts.

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