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

DTC No. DTC Detection Condition Trouble Area
B2785

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

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

  • Certification ECU (Smart key ECU assembly)

  • Main body ECU (Instrument panel junction block assembly)

  • Steering lock ECU (Steering lock actuator assembly)

  • ID code box (Immobiliser code ECU)

  • Wire harness

WIRING DIAGRAM

A017BT0E15

INSPECTION PROCEDURE

Note

When using the intelligent tester with the ignition switch off to troubleshoot:

Connect the intelligent tester to the vehicle, 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 D36 connector.

    2. Disconnect the 1E connector.

    3. Disconnect the D28 connector.

    4. Disconnect the D10 connector.

      A017FD7E01

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

      Standard resistance
      Tester Connection Condition Specified Condition
      D36-10 (LIN) - D28-3 (LIN1) Always Below 1 Ω
      D36-10 (LIN) - 1E-7 (LIN1) Always Below 1 Ω
      D36-10 (LIN) - D10-5 (LIN) Always Below 1 Ω
      D36-10 (LIN) - Body ground Always 10 kΩ or higher

    6. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Condition Specified Condition
      D36-10 (LIN) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK FOR DTC


    1. Connect the D36, D28 and D10 connectors.

    2. Check for DTC.

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

    B

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK) Click here

    A

  3. CHECK FOR DTC


    1. Connect the 1E connector.

    2. Disconnect the D10 connector.

    3. Check for DTC.

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

    B

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

    A

  4. CHECK FOR DTC


    1. Connect the D10 connector.

    2. Disconnect the D28 connector.

    3. Check for DTC.

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

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU) Click here

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  5. REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)


    1. Replace the main body ECU with a normally-functioning or a new one.


    NEXT

  6. CHECK FOR DTC


    1. Recheck for DTC.

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

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

    END

  7. REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)


    1. Replace the steering lock ECU (steering lock actuator assembly) with a new one Click here.


    NEXT

  8. CHECK FOR DTC


    1. Recheck for DTC.

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

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

    END

  9. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


    1. Replace the ID code box (immobiliser code ECU) with a new one.


    NEXT

  10. CHECK FOR DTC


    1. Recheck for DTC.

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

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

    END