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Home >> Nissan-Datsun >> 2021 >> NV2500 HD S >> Repair and Diagnosis >> External Pages >> Different car >> Section 604 (Can System (Circuit Diagnosis)) >> Circuit Diagnosis >> Vehicle Can Communication 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. CONNECTOR INSPECTION 
    1. Turn the ignition switch OFF.
    2. Disconnect the battery cable from the negative terminal.
    3. Disconnect all the unit connectors on vehicle CAN communication circuit.
    4. Check terminals and connectors for damage, bend and loose connection.

    Is the inspection result normal?

    YES

    GO TO 2.

    NO

    Repair the terminal and connector.

  2. CHECK HARNESS CONTINUITY (OPEN CIRCUIT) 

    Check the continuity between the 3CH CAN gateway harness connector and the combination meter harness connector.

    3CH CAN gateway harness connector

    Combination meter harness connector

    Continuity

    Connector No.

    Terminal No.

    Connector No.

    Terminal No.

    M6

    1

    M24

    39

    Existed

    2

    38

    Existed

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Check the harness and repair the root cause.

  3. CHECK HARNESS CONTINUITY (SHORT CIRCUIT) 

    Check the continuity between the 3CH CAN gateway harness connector terminals.

    3CH CAN gateway harness connector

    Continuity

    Connector No.

    Terminal No.

    M6

    1

    2

    Not existed

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Check the harness and repair the root cause.

  4. CHECK HARNESS CONTINUITY (SHORT CIRCUIT) 

    Check the continuity between the 3CH CAN gateway harness connector and the ground.

    3CH CAN gateway harness connector

    Ground

    Continuity

    Connector No.

    Terminal No.

    M6

    1

    Not existed

    2

    Not existed

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Check the harness and repair the root cause.

  5. CHECK ECM AND BCM TERMINATION CIRCUIT 
    1. Remove the ECM and the BCM.
    2. Check the resistance between the ECM terminals.
      • With VQ35DD

        ECM

        Resistance (Ohm)

        Terminal No.

        176

        175

        Approx. 108 - 132
      • With VQ35DE

        ECM

        Resistance (Ohm)

        Terminal No.

        114

        113

        Approx. 108 - 132
    3. Check the resistance between the BCM terminals.

      BCM

      Resistance (Ohm)

      Terminal No.

      60

      59

      Approx. 108 - 132

    Is the measurement value within the specification?

    YES

    GO TO 6.

    NO

    Replace the ECM and/or the BCM.

  6. CHECK SYMPTOM 

    Connect all the connectors. Check if the symptoms described in the "Symptom (Results from interview with customer)" are reproduced.

    Inspection result

    Reproduced

    GO TO 7.

    NO

    Start the diagnosis again. Follow the trouble diagnosis procedure when past error is detected.

  7. CHECK UNIT REPRODUCTION 

    Perform the reproduction test as per the following procedure for each unit.

    1. Turn the ignition switch OFF.
    2. Disconnect the battery cable from the negative terminal.
    3. Disconnect one of the unit connectors of vehicle CAN communication circuit.
      NOTE: ECM and BCM have a termination circuit. Check other units first.
    4. Connect the battery cable to the negative terminal. Check if the symptoms described in the "Symptom (Results from interview with customer)" are reproduced.
      NOTE: Although unit-related error symptoms occur, do not confuse them with other symptoms.

    Inspection result

    Reproduced

    Connect the connector. Check other units as per the above procedure.

    NO

    Replace the unit whose connector was disconnected.

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