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Home >> Infiniti >> 2015 >> Q50 Base, RWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> LAN System (Can) (Exc Hybrid) >> DTC/Circuit Diagnosis >> Can Communication 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 CAN communication system.
    4. Check terminals and connectors for damage, bend and loose connection.

    Is the inspection result normal?

    YES 

    GO TO STEP 2  .

    NO 

    Repair the terminal and connector.

  2. CHECK HARNESS CONTINUITY (SHORT CIRCUIT)

    Check the continuity between the data link connector terminals.

    Data link connector Continuity
    Connector No. Terminal No.
    M25 6 14 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 3  .

    NO 

    Check the harness and repair or replace [if shield line or fuse block (J/B) is short] the root cause.

  3. CHECK HARNESS CONTINUITY (SHORT CIRCUIT)

    Check the continuity between the data link connector and the ground.

    Data link connector Ground Continuity
    Connector No. Terminal No.
    M25 6 Not existed
    14 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 4  .

    NO 

    Check the harness and repair or replace [if shield line or fuse block (J/B) is short] the root cause.

  4. CHECK ECM AND BCM TERMINATION CIRCUIT

    1. Remove the ECM and the BCM.
    2. Check the resistance between the ECM terminals.
      ECM Resistance (Ω)
      Terminal No.
      114 113 Approx. 108 - 132
    3. Check the resistance between the BCM terminals.
      BCM Resistance (Ω)
      Terminal No.
      60 59 Approx. 108 - 132

    Is the measurement value within the specification?

    YES 

    GO TO STEP 5  .

    NO 

    Replace the ECM and/or the BCM.

  5. 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 STEP 6  .

    Non - reproduced 

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

  6. 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 CAN communication system.
      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.

    Non - reproduced 

    Replace the unit whose connector was disconnected.

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