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Home >> Infiniti >> 2017 >> QX30 Base >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> LAN System (Can) >> DTC/Circuit Diagnosis >> BCM - Left Front Door Control Unit Circuit >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK HARNESS CONNECTOR CONNECTION

    Check the following harness connector for disconnection or looseness.

    • BCM
    • Harness connector M59
    • Harness connector D32
    • Left front door control unit

    Is the inspection result normal?

    YES 

    GO TO STEP 2  .

    NO 

    Securely connect the harness connectors.

  2. CHECK POWER SUPPLY AND GROUND CIRCUIT

    Check power supply and ground circuit for the following unit.

    Is the inspection result normal?

    YES 

    GO TO STEP 3  .

    NO 

    Repair or replace the malfunctioning part.

  3. CHECK CIRCUIT (SHORT TO BATTERY)

    1. Turn ignition switch OFF.
    2. Disconnect the following unit connectors.
      • BCM
      • Left front door control unit
    3. Check voltage between BCM harness connector and ground.
      Terminals Voltage
      (Approx.)
      + -
      BCM Ground
      Connector Terminal
      M25 8 - 0 V
      9

    Is the inspection result normal?

    YES 

    GO TO STEP 4  .

    NO 

    Repair or replace harness.

  4. CHECK CIRCUIT (SHORT TO GROUND)

    Check continuity between BCM harness connector and ground.

    BCM Ground Continuity
    Connector Terminal
    M25 8 - Not existed
    9

    Is the inspection result normal?

    YES 

    GO TO STEP 5  .

    NO 

    Repair or replace harness.

  5. CHECK CIRCUIT (SHORT WITH CAN-H AND CAN-L)

    Check continuity between BCM harness connector terminals.

    BCM Continuity
    Connector Terminal Connector Terminal
    M25 8 M25 9 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 6  .

    NO 

    Repair or replace harness.

  6. CHECK CIRCUIT (OPEN)

    Check continuity between the following unit harness connectors.

    • BCM
    • Left front door control unit
      BCM - LEFT FRONT DOOR CONTROL UNIT

      BCM Left front door control unit Continuity
      Connector Terminal Connector Terminal
      M25 8 D12 22 Existed
      9 21

    Is the inspection result normal?

    YES 

    INSPECTION END

    NO 

    Repair or replace harness.