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) intermittently monitors the LIN communication bus between the components related to certification. DTC B2785 is output when a malfunction in the LIN communication bus between the components related to certification is detected continuously 3 times.

DTC Code DTC Detection Condition Trouble Area
B2785 The certification ECU (smart key ECU assembly) detects a malfunction in the LIN communication bus between components related to certification continuously 3 times.

  • Certification ECU (smart key ECU assembly)

  • Main body ECU (cowl side junction block LH)

  • ID code box (immobiliser code ECU)

  • Steering lock ECU

  • Harness or connector

WIRING DIAGRAM

A0157D7E03

INSPECTION PROCEDURE

Note

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

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

Tech Tips

When DTC B2785 and B2287 are output simultaneously, perform the troubleshooting for DTC B2785 first.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - MASTER SWITCH)


    1. A015BP6E01

      Disconnect the 2D and E29 ECU connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E29-10 (LIN) - 2D-20 (LIN1) Always Below 1 Ω
      E29-10 (LIN) - Body ground Always 10 kΩ or higher

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      E29-10 (LIN) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK FOR DTC


    1. Reconnect the E26 and E29 ECU connectors.

    2. Reconnect the E28 box 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 (COWL SIDE JUNCTION BLOCK LH) Click here

    A

  3. CHECK FOR DTC


    1. Reconnect the 2D ECU connector.

    2. Disconnect the E26 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 STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY) Click here

    A

  4. CHECK FOR DTC


    1. Reconnect the E26 ECU connector.

    2. Disconnect the E28 box 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) Click here

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  5. REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH)


    1. Temporarily replace the main body ECU (cowl side junction block LH) with a new or normally functioning one.

    2. Clear the DTC Click here.


    NEXT

  6. CHECK FOR DTC


    1. Recheck for DTCs.

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

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

    END (MAIN BODY ECU IS DEFECTIVE)

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


    1. Temporarily replace the steering lock ECU with a new or normally functioning one Click here.

    2. Clear the DTC Click here.


    NEXT

  8. CHECK FOR DTC


    1. Recheck for DTCs.

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

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

    END (STEERING LOCK ECU IS DEFECTIVE)

  9. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


    1. Temporarily replace the ID code box immobiliser code ECU with a new or normally functioning one.

    2. Clear the DTC Click here.


    NEXT

  10. CHECK FOR DTC


    1. Recheck for DTCs Click here.

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

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    A

    END (ID CODE BOX IS DEFECTIVE)