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Home >> Infiniti >> 2018 >> QX30 Essential, FWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Can System (Circuit Diagnosis) >> Circuit Diagnosis >> Body Can Communication 1 >> Diagnosis Procedure

Diagnosis Procedure

  1. ERROR ECU CONFIRMATION 

    Confirm whether there is error in one ECU or plural ECU on CAN diagnosis function with CONSULT.

    Is error in one ECU or plural ECU?

    One ECU

    GO TO 2.

    Plural ECU

    GO TO 3.

  2. CHECK ECU CIRCUIT 

    Check a circuit for applicable ECU. Refer to following.

    Unit name

    Circuit

    Reference

    A/C auto amp.

    Circuit between the CAN potential distributor electrical connector (Body) and the A/C auto amp.

    Diagnosis Procedure 

    BCM

    Circuit between the CAN potential distributor electrical connector (Body) and the BCM (Body Control Module)

    Diagnosis Procedure 

    CAN gateway

    Circuit between the CAN potential distributor electrical connector (Body) and the CAN gateway

    Diagnosis Procedure 

    Combination meter

    Circuit between the CAN potential distributor electrical connector (Body) and the combination meter

    Diagnosis Procedure 

    Driver seat control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the driver seat control unit

    Diagnosis Procedure 

    Electronic ignition switch control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the electronic ignition switch control unit

    Diagnosis Procedure 

    Intelligent Key unit

    Circuit between the CAN potential distributor electrical connector (Body) and the Intelligent Key unit

    Diagnosis Procedure 

    Passenger seat control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the passenger seat control unit

    Diagnosis Procedure 

    Right front door control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the right front door control unit

    Diagnosis Procedure 

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Repair or replace applicable parts.

  3. CHECK CAN CIRCUIT VOLTAGE 
    1. Turn ignition switch ON.
    2. Check voltage between CAN potential distributor electrical connector (Body) harness connector each terminals.

      Terminals

      Voltage

      (Approx.)

      +

      -

      CAN potential distributor electrical connector (Body)

      Terminal

      Terminal

      CAN-H

      Ground

      2.5 - 2.7 V

      CAN-L

      Ground

      2.1 - 2.3 V

      CAN-H

      CAN-L

      0.2 - 0.4 V

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Intermittent Incident .

    NO

    GO TO 4.

  4. CHECK HARNESS CONNECTOR CONDITION 
    1. Turn ignition switch OFF.
    2. Check each harness connector connected to CAN potential distributor electrical connector for proper connection, locking, loose contact, damage, contamination and corrosion.

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Securely connects or repair the harness connectors.

  5. CHECK CAN POTENTIAL DISTRIBUTOR ELECTRICAL CONNECTOR 
    1. Turn ignition switch OFF.
    2. Disconnect all of harness connector from CAN potential distributor electrical connector (Body).
    3. Check CAN potential distributor electrical connector (Body). Refer to Component Inspection [CAN Potential Distributor Electrical Connector(Body)] .

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Replace CAN potential distributor electrical connector (Body).

  6. POSSIBLE CAUSE CONFIRMATION 
    1. Turn ignition switch ON.
    2. Check the voltage between CAN potential distributor electrical connector (Body) terminals (CAN-H and CAN-L).
      NOTE: [Recommend] Check CAN potential distributor electrical connector (Body) terminals that harness connector is not connected.
    3. Disconnect each harness connector from CAN potential distributor electrical connector (Body) one by one.
    4. Check the voltage change when the harness connector just disconnected.

      Terminals

      Condition

      Voltage

      (Approx.)

      +

      -

      CAN potential distributor electrical connector (Body)

      Terminal

      Terminal

      CAN-H

      CAN-L

      When the harness connector just disconnected.

      No change

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Intermittent Incident .

    NO

    GO TO 7.

  7. CHECK SHORT CIRCUIT 

    Check the possible cause circuit for short to battery or ground.

    Unit name

    Circuit

    Reference

    A/C auto amp.

    Circuit between the CAN potential distributor electrical connector (Body) and the A/C auto amp.

    Diagnosis Procedure 

    BCM

    Circuit between the CAN potential distributor electrical connector (Body) and the BCM (Body Control Module)

    Diagnosis Procedure 

    CAN gateway

    Circuit between the CAN potential distributor electrical connector (Body) and the CAN gateway

    Diagnosis Procedure 

    Combination meter

    Circuit between the CAN potential distributor electrical connector (Body) and the combination meter

    Diagnosis Procedure 

    Driver seat control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the driver seat control unit

    Diagnosis Procedure 

    Electronic ignition switch control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the electronic ignition switch control unit

    Diagnosis Procedure 

    Intelligent Key unit

    Circuit between the CAN potential distributor electrical connector (Body) and the Intelligent Key unit

    Diagnosis Procedure 

    Passenger seat control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the passenger seat control unit

    Diagnosis Procedure 

    Right front door control unit

    Circuit between the CAN potential distributor electrical connector (Body) and the right front door control unit

    Diagnosis Procedure 

    Is the inspection result normal?

    YES

    Replace applicable ECU.

    NO

    Repair or replace harness.