LIN COMMUNICATION SYSTEM, Diagnostic DTC:B2785

DTC Code DTC Name
B2785 Communication Malfunction between ECUs Connected by LIN

DESCRIPTION

The certification ECU intermittently monitors the LIN communication bus between the components related to certification. DTC B2785 is stored when a malfunction in the LIN communication bus between the components related to certification is detected 3 times consecutively.

DTC No. Detection Item DTC Detection Condition Trouble Area
B2785 Communication Malfunction between ECUs Connected by LIN The certification ECU detects a malfunction in the LIN communication bus between components related to certification 3 times consecutively.

  • Certification ECU (smart key ECU assembly)

  • ID code box (immobiliser code ECU)

  • Steering lock ECU (steering lock actuator or upper bracket assembly)

  • Harness or connector

WIRING DIAGRAM

B002C5TE07
*a Certification ECU (Smart Key ECU Assembly)
*b ID Code Box (Immobiliser Code ECU)
*c Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly)
*d LIN Communication Line

CAUTION / NOTICE / HINT

Note


  • When using the GTS with the engine switch off to troubleshoot:

    Connect the GTS to the vehicle, and turn a courtesy light switch on and off at 1.5 seconds intervals until communication between the GTS and vehicle begins.

  • If the certification ECU (smart key ECU assembly), ID code box (immobiliser Code ECU) or steering lock ECU (steering lock actuator or upper bracket assembly) is replaced, refer to the Service Bulletin.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > Entry&Start > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Entry&Start > Trouble Codes
      Result
      Result Proceed to
      DTC B2785 is not output A
      DTC B2785 is output B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

  3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - EACH ECU)


    1. Disconnect the K74 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the K60 ID code box (immobiliser code ECU) connector.

    3. Disconnect the K20 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      K74-17 (LIN) - K20-5 (LIN) Always Below 1 Ω
      K74-17 (LIN) - K60-2 (LIN1) Always Below 1 Ω
      K74-17 (LIN) or K20-5 (LIN) - Body ground Always 10 kΩ or higher
      K74-17 (LIN) or K60-2 (LIN1) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)


    1. Temporarily replace the steering lock ECU (steering lock actuator or upper bracket assembly) with a new or normally.

      Click here

    2. Clear the DTCs.

      Click here


      Body Electrical > Entry&Start > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Entry&Start > Trouble Codes
      Result
      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    B

    END (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) WAS DEFECTIVE)

    A

  6. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


    1. Temporarily replace the ID code box (Immobiliser Code ECU) with a new or normally.

    2. Clear the DTCs.

      Click here


      Body Electrical > Entry&Start > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Entry&Start > Trouble Codes
      Result
      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    B

    END (ID CODE BOX (IMMOBILISER CODE ECU) WAS DEFECTIVE)