LIN COMMUNICATION SYSTEM, Diagnostic DTC:B2785

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

DESCRIPTION

If the certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more, DTC B2785 will be stored.

DTC No. Detection Item DTC Detection Condition Trouble Area
B2785 Communication Malfunction between ECUs Connected by LIN

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

  • The certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more.

  • Certification ECU (smart key ECU assembly)

  • Steering lock ECU (steering lock actuator or upper bracket assembly)

  • ID code box (immobiliser code ECU)*

  • Wire harness or connector

WIRING DIAGRAM

B006YV7E02

CAUTION / NOTICE / HINT

Note


  • Before performing the inspection, check that DTC B2786 or B278C is not output.

    Click here

  • When using the GTS with the ignition switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Entry&Start(CAN). While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.

  • Before replacing the certification ECU (smart key ECU assembly), ID code box (immobiliser code ECU)* or steering lock ECU (steering lock actuator or upper bracket assembly), refer to Service Bulletin.


    • *: w/ ID Code Box

PROCEDURE


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


    1. Disconnect the K62 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the K65 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

    3. Disconnect the K139 ID code box (immobiliser code ECU) connector.*


      • *: w/ ID Code Box

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

      Note

      Make sure that each ECU is in sleep mode before performing the inspection. To enter sleep mode, turn the ignition switch from ON to off and wait for 180 seconds or more without operating any switches.*


      • *: w/ ID Code Box

      Standard Resistance
      w/ ID Code Box
      Tester Connection Condition Specified Condition
      K62-13 (LIN) - K65-5 (LIN) Ignition switch off Below 1 Ω
      K62-13 (LIN) - K139-2 (LIN) Ignition switch off Below 1 Ω
      K62-13 (LIN), K65-5 (LIN) or K139-2 (LIN) - Body ground Ignition switch off 10 kΩ or higher
      w/o ID Code Box
      Tester Connection Condition Specified Condition
      K62-13 (LIN) - K65-5 (LIN) Always Below 1 Ω
      K62-13 (LIN) or K65-5 (LIN) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))


    1. Connect the K62 certification ECU (smart key ECU assembly) connector.

    2. Connect the K139 ID code box (immobiliser code ECU) connector.*


      • *: w/ ID Code Box

    3. Clear the DTCs.


      Body Electrical > Entry&Start > Clear DTCs

    4. Recheck for DTCs.


      Body Electrical > Entry&Start > Trouble Codes
      Result
      Result Proceed to
      DTC B2785 is output (w/o ID Code Box) A
      DTC B2785 is output (w/ ID Code Box) B
      DTC B2785 is not output C

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    C

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) for Manual Tilt and Manual Telescopic Steering Column: Click here
    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) for Power Tilt and Power Telescopic Steering Column: Click here

    B

  3. CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))


    1. Connect the K65 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

    2. Disconnect the K139 ID code box (immobiliser code ECU) connector.

    3. Clear the DTCs.


      Body Electrical > Entry&Start > Clear DTCs

    4. Recheck for DTCs.


      Body Electrical > Entry&Start > Trouble Codes
      Result
      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)