LIN COMMUNICATION SYSTEM, Diagnostic DTC:B2785

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

DESCRIPTION

The certification ECU (smart key ECU assembly) monitors communication between all the ECUs connected to the certification bus lines. When the certification ECU (smart key ECU assembly) detects errors in communication with all the ECUs connected to the certification bus lines at a set interval and 3 times in a row, DTC B2785 will be output.

DTC Code DTC Detection Condition Trouble Area
B2785

  • Errors in LIN communication between ECUs and an open or short in communication lines

  • LIN communication from the certification ECU (smart key ECU assembly) stops for a set amount of time or more

  • Certification ECU (Smart key ECU assembly)

  • Main body ECU

  • Steering lock ECU (Steering lock actuator assembly)

  • ID code box (Immobiliser code ECU)

  • Wire harness or connector

WIRING DIAGRAM

A01CAVKE31

INSPECTION PROCEDURE

Note


  • If the certification ECU (smart key ECU assembly) is replaced, register the key.

  • If the steering lock ECU (steering lock actuator assembly) is replaced, register the ECU code.

  • If the ID code box (immobiliser code ECU) is replaced, register the ECU code and ECU communication ID.

  • When using the intelligent tester to troubleshoot with the engine switch off:

    Connect the intelligent tester to the DLC3, and turn the courtesy switch on and off at 1.5-second intervals until communication between the tester and vehicle begins.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - EACH ECU)


    1. Disconnect the G20, 4A, G15 and G22 ECU connectors.

    2. Measure the resistance and voltage according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      G20-10 (LIN) - G22-5 (LIN) Always Below 1 Ω
      G20-10 (LIN) - 4A-20 (LIN1) Always Below 1 Ω
      G20-10 (LIN) - G15-3 (LIN1) Always Below 1 Ω
      G20-10 (LIN) - Body ground Always 10 kΩ or higher
      Standard Voltage
      Tester Connection Condition Specified Condition
      G20-10 (LIN) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK DTC OUTPUT (STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY))


    1. Reconnect the G20, 4A and G15 ECU connectors.

    2. Clear the DTC Click here.

    3. Recheck for DTCs.

      Result
      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    B

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY) Click here

    A

  3. CHECK DTC OUTPUT (MAIN BODY ECU)


    1. Reconnect the G15 ECU connector.

    2. Disconnect the 4A ECU connector.

    3. Clear the DTC Click here.

    4. Recheck for DTCs.

      Result
      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    B

    REPLACE MAIN BODY ECU Click here

    A

  4. CHECK DTC OUTPUT (ID CODE BOX (IMMOBILISER CODE ECU))


    1. Reconnect the G22 ECU connector.

    2. Disconnect the G15 ECU connector.

    3. Clear the DTC Click here.

    4. Recheck for DTCs.

      Result
      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)