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Home >> Infiniti >> 2018 >> QX30 Essential, FWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Can System (Circuit Diagnosis) >> Circuit Diagnosis >> Av Branch Line Circuit >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK CONNECTOR 
    1. Turn the ignition switch OFF.
    2. Disconnect the battery cable from the negative terminal.
    3. Check the following terminals and connectors for damage, bend and loose connection (unit side and connector side).
      • Display control unit
      • CAN gateway

    Is the inspection result normal?

    YES

    GO TO 2.

    NO

    Repair the terminal and connector.

  2. CHECK HARNESS CONTINUITY (OPEN CIRCUIT) 
    1. Disconnect the connector of CAN gateway.
    2. Check the continuity between the CAN gateway harness connector terminals.

      CAN gateway harness connector

      Continuity

      Connector No.

      Terminal No.

      Connector No.

      Terminal No.

      M218

      20

      M217

      9

      Existed

      19

      3

      Existed

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Check the harness and repair the root cause (Multifunction media CAN communication circuit).

  3. CHECK HARNESS FOR OPEN CIRCUIT 
    1. Connect the connector of CAN gateway.
    2. Disconnect the connector of display control unit.
    3. Check the resistance between the display control unit harness connector terminals.

      Display control unit harness connector

      Resistance (Ohm)

      Connector No.

      Terminal No.

      M52

      59

      47

      Approx. 54 - 66

    Is the measurement value within the specification?

    YES

    GO TO 4.

    NO

    Repair the display control unit branch line.

  4. CHECK POWER SUPPLY AND GROUND CIRCUIT 

    Check the power supply and the ground circuit of the display control unit. Refer to Diagnosis Procedure .

    Is the inspection result normal?

    YES

    Replace the display control unit. Refer to Removal and Installation .

    YES

    Error was detected in the display control unit branch line.

    NO

    Repair the power supply and the ground circuit.