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Home >> Infiniti >> 2017 >> QX30 Base >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> LAN System (Can) >> DTC/Circuit Diagnosis >> Front End Can Communication >> 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 STEP 2  .

    Plural ECU 

    GO TO STEP 3  .

  2. CHECK ECU CIRCUIT

    Check a circuit for applicable ECU. Refer to following.

    Unit name Circuit Reference
    Electronic ignition switch control unit Circuit between the CAN potential distributor electrical connector (Front end) and the electronic ignition switch control unit DIAGNOSIS PROCEDURE 
    Front camera unit Circuit between the CAN potential distributor electrical connector (Front end) and the front camera unit DIAGNOSIS PROCEDURE 
    Headlamp control unit LH Circuit between the CAN potential distributor electrical connector (Front end) and the front combination lamp LH DIAGNOSIS PROCEDURE 
    Headlamp control unit RH Circuit between the CAN potential distributor electrical connector (Front end) and the front combination lamp RH DIAGNOSIS PROCEDURE 
    Side radar LH Circuit between the CAN potential distributor electrical connector (Front end) and the side radar LH DIAGNOSIS PROCEDURE 
    Side radar RH Circuit between the CAN potential distributor electrical connector (Front end) and the side radar RH DIAGNOSIS PROCEDURE 

    Is the inspection result normal?

    YES 

    GO TO STEP 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 (Front end) harness connector each terminals.
      Terminals Voltage
      (Approx.)
      + -
      CAN potential distributor electrical connector (Front end)
      Terminal Terminal
      CAN-H Ground 3.0 - 3.2 V
      CAN-L Ground 2.8 - 3.0 V
      CAN-H CAN-L 0.1 - 0.2 V

    Is the inspection result normal?

    YES 

    Check intermittent incident. Refer to INTERMITTENT INCIDENT .

    NO 

    GO TO STEP 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 STEP 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 (Front end).
    3. Check CAN potential distributor electrical connector (Front end). Refer to COMPONENT INSPECTION [CAN POTENTIAL DISTRIBUTOR ELECTRICAL CONNECTOR (FRONT END)] .

    Is the inspection result normal?

    YES 

    GO TO STEP 6  .

    NO 

    Replace CAN potential distributor electrical connector (Front end).

  6. POSSIBLE CAUSE CONFIRMATION

    1. Turn ignition switch ON.
    2. Check the voltage between CAN potential distributor electrical connector (Front end) terminals (CAN-H and CAN-L).
      NOTE:

      [Recommend] Check CAN potential distributor electrical connector (Front end) terminals that harness connector is not connected.

    3. Disconnect each harness connector from CAN potential distributor electrical connector (Front end) one by one.
    4. Check the voltage change when the harness connector just disconnected.
      Terminals Condition Voltage
      (Approx.)
      + -
      CAN potential distributor electrical connector (Front end)
      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 STEP 7  .

  7. CHECK SHORT CIRCUIT

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

    Unit name Circuit Reference
    Electronic ignition switch control unit Circuit between the CAN potential distributor electrical connector (Front end) and the electronic ignition switch control unit DIAGNOSIS PROCEDURE 
    Front camera unit Circuit between the CAN potential distributor electrical connector (Front end) and the front camera unit DIAGNOSIS PROCEDURE 
    Headlamp control unit LH Circuit between the CAN potential distributor electrical connector (Front end) and the front combination lamp LH DIAGNOSIS PROCEDURE 
    Headlamp control unit RH Circuit between the CAN potential distributor electrical connector (Front end) and the front combination lamp RH DIAGNOSIS PROCEDURE 
    Side radar LH Circuit between the CAN potential distributor electrical connector (Front end) and the side radar LH DIAGNOSIS PROCEDURE 
    Side radar RH Circuit between the CAN potential distributor electrical connector (Front end) and the side radar RH DIAGNOSIS PROCEDURE 

    Is the inspection result normal?

    YES 

    Replace applicable ECU.

    NO 

    Repair or replace harness.

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