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 stored.

DTC No. DTC Detection Condition Trouble Area
B2785

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

  • LIN communication from the certification ECU (smart key ECU assembly) detects errors in communication 3 times in a row.

  • Certification ECU (smart key ECU assembly)

  • Steering lock ECU (steering lock actuator assembly)

  • ID code box (immobiliser code ECU)*

  • Wire harness or connector

*: w/ Entry Function on Driver Door except TMMK Made

WIRING DIAGRAM

B000M96E20

INSPECTION PROCEDURE

Note


  • If the certification ECU (smart key ECU assembly) is replaced, register the keys (refer to the Service Bulletin).

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

  • If the ID code box (immobiliser code ECU) is replaced, register the ECU code and ECU communication ID (refer to the Service Bulletin).*

  • When using the intelligent tester to troubleshoot with the ignition 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 intelligent tester and vehicle begins.

    *: w/ Entry Function on Driver Door except TMMK Made

PROCEDURE


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


    1. Disconnect the I78 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the I24 steering lock ECU (steering lock actuator assembly) connector.

    3. Disconnect the I20 ID code box (immobiliser code ECU) connector*.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I78-17 (LIN) - I24-5 (LIN) Always Below 1 Ω
      I78-17 (LIN) - I20-2 (LIN1)* Always Below 1 Ω
      I78-17 (LIN) - Body ground Always 10 kΩ or higher

      *: w/ Entry Function on Driver Door except TMMK Made


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK DTC OUTPUT (STEERING LOCK ECU)


    1. Reconnect the I78 certification ECU (smart key ECU assembly) connector.

    2. Reconnect the I20 ID code box (immobiliser code ECU) connector*.

    3. Clear the DTC Click here.

    4. Recheck for DTCs.

      *: w/ Entry Function on Driver Door except TMMK Made

      Result
      Result Proceed to
      DTC B2785 is output (w/ Entry Function on Driver Door except TMMK Made) A
      DTC B2785 is output (w/o Entry Function on Driver Door or for TMMK Made) B
      DTC B2785 is not output C

    B

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    C

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

    A

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


    1. Reconnect the I24 steering lock ECU (steering lock actuator assembly) connector.

    2. Disconnect the I20 ID code box (immobiliser code 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)