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LIN COMMUNICATION SYSTEM, Diagnostic DTC:B2785

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

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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.

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - EACH ECU)


    1. Disconnect the D36 connector.

    2. Disconnect the 1E connector.

    3. Disconnect the D28 connector.

    4. A017FD7E01

      Disconnect the D10 connector.

    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

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    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

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    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

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    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

  5. Click here

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)


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


  6. Click here

    CHECK FOR DTC


    1. Recheck for DTC.

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

  7. Click here

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)


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


  8. Click here

    CHECK FOR DTC


    1. Recheck for DTC.

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

  9. Click here

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)


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


  10. Click here

    CHECK FOR DTC


    1. Recheck for DTC.

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

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

  12. Click here

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  13. Click here

    END