LEMON Manuals: Even more car manuals for everyone
Home >> Infiniti >> 2024 >> QX55 Essential >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Can System (DTC/Circuit Diagnosis) >> Circuit Diagnosis >> Vehicle Can Communication 2 Circuit >> Diagnosis Procedure

Diagnosis Procedure

  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 2 circuit.
    4. Check terminals and connectors for damage, bend and loose connection.

    Is the inspection result normal?

    >>

    GO TO 2.

    >>

    Repair the terminal and connector.

  2. CHECK HARNESS CONTINUITY (OPEN CIRCUIT) 

    Check the continuity between the 6CH CAN gateway harness connector and the BCM harness connector.

    6CH CAN gateway harness connector BCM harness connector Continuity
    Connector No. Terminal No. Connector No. Terminal No.
    M462 4 M18 6 Existed
    16 5 Existed

    Is the inspection result normal?

    >>

    GO TO 3.

    >>

    Check the harness and repair the root cause.

  3. CHECK HARNESS CONTINUITY (SHORT CIRCUIT) 

    Check the continuity between the 6CH CAN gateway harness connector terminals.

    6CH CAN gateway harness connector Continuity
    Connector No. Terminal No.
    M462 4 16 Not existed

    Is the inspection result normal?

    >>

    GO TO 4.

    >>

    Check the harness and repair the root cause.

  4. CHECK HARNESS CONTINUITY (SHORT CIRCUIT) 

    Check the continuity between the 6CH CAN gateway harness connector and the ground.

    6CH CAN gateway harness connector Ground Continuity
    Connector No. Terminal No.
    M462 4 Not existed
    16 Not existed

    Is the inspection result normal?

    >>

    GO TO 5.

    >>

    Check the harness and repair the root cause.

  5. CHECK TERMINATION CIRCUIT 
    1. Remove the 6CH CAN gateway and the BCM.
    2. Check the resistance between the 6CH CAN gateway terminals.
      6CH CAN gateway Resistance (Ω)
      Terminal No.
      4 16 Approx. 108 - 132
    3. Check the resistance between the BCM terminals.
      BCM Resistance (Ω)
      Terminal No.
      6 5 Approx. 108 - 132

    Is the measurement value within the specification?

    >>

    GO TO 6.

    >>

    Replace the 6CH CAN gateway 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.

    >>

    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 2 circuit.
      NOTE: SYMBOL 6CH CAN gateway 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: SYMBOL 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.

    >>

    Replace the unit whose connector was disconnected.

scientia non olet · About LEMON Manuals