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 bus lines. When the certification ECU (smart key ECU assembly) detects errors in communication with all the ECUs connected to the certification ECU 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 the certification ECU (smart key ECU assembly) stops for a set amount of time or more

  • Certification ECU (smart key ECU assembly)

  • Power source control ECU

  • Steering lock ECU (steering lock actuator assembly)

  • ID code box (immobiliser code ECU)

  • Wire harness or connector

WIRING DIAGRAM

A015ZYCE02

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.

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTC Click here.

    2. Recheck for DTC.

      OK
      B2785 is not output.

    NG

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - EACH ECU) Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here

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


    1. Disconnect the P33, J55, J69 and J29 ECU connectors.

      A015YRUE01

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P33-10 (LIN) - J29-5 (LIN) Always Below 1 Ω
      P33-10 (LIN) - J55-30 (LIN1) Always Below 1 Ω
      P33-10 (LIN) - J69-3 (LIN1) Always Below 1 Ω
      P33-10 (LIN) - Body ground Always 10 kΩ or higher
      Standard Voltage
      Tester Connection Condition Specified Condition
      P33-10 (LIN) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK FOR DTC (STEERING LOCK ECU)


    1. Reconnect the P33, J55 and J69 connectors.

    2. Clear the DTC Click here.

    3. Recheck for DTC.

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

    B

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)

    A

  4. CHECK FOR DTC (ID CODE BOX)


    1. Reconnect the J29 connector.

    2. Disconnect the J69 connector.

    3. Clear the DTC Click here.

    4. Recheck for DTC.

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

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    A

  5. REPLACE POWER SOURCE CONTROL ECU


    1. Replace the power source control ECU.


    NEXT

  6. CHECK FOR DTC


    1. Clear the DTC Click here.

    2. Recheck for DTC.

      OK
      B2785 is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

    END (POWER SOURCE CONTROL ECU IS DEFECTIVE)