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. 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

  • LIN communication error detected by the certification ECU (smart key ECU assembly) 3 times in a row.

  • Certification ECU (smart key ECU assembly)

  • Steering lock ECU (steering lock actuator assembly)

  • ID code box (immobiliser code ECU)

  • Power management control ECU

  • Wire harness or connector

  • STRG LOCK fuse

  • SMART fuse

  • AM2 fuse

WIRING DIAGRAM

A01MTXYE02

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • If the certification ECU (smart key ECU assembly), steering lock ECU (steering lock actuator assembly), ID code box (immobiliser code ECU) or power management control ECU is replaced, refer to Service Bulletin.

  • Before performing the inspection, check that DTC B2287, B2786, B2789 or B278C is not output.

    Click here

  • When using the GTS with the power 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.

PROCEDURE


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


    1. Disconnect the K8 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the K28 steering lock ECU (steering lock actuator assembly) connector.

    3. Disconnect the K83 ID code box (immobiliser code ECU) connector.

    4. Disconnect the K33 power management control ECU connector.

    5. 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 power switch from on (IG) to off and wait for 60 seconds or more without operating any switches.

      Standard Resistance
      Tester Connection Condition Specified Condition
      K8-21 (LIN) - K28-5 (LIN) Power switch off Below 1 Ω
      K8-21 (LIN) - K83-2 (LIN1) Power switch off Below 1 Ω
      K8-21 (LIN) - K33-11 (LIN2) Power switch off Below 1 Ω
      K8-21 (LIN) - Body ground Power switch off 10 kΩ or higher
      K28-5 (LIN) - Body ground Power switch off 10 kΩ or higher
      K83-2 (LIN1) - Body ground Power switch off 10 kΩ or higher
      K33-11 (LIN2) - Body ground Power switch off 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK DTC OUTPUT (STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY))


    1. Reconnect the K8 certification ECU (smart key ECU assembly) connector.

    2. Reconnect the K83 ID code box (immobiliser code ECU) connector.

    3. Reconnect the K33 power management control ECU connector.

    4. Clear the DTCs.

      Click here


      Body Electrical > Entry&Start > Clear DTCs

    5. Recheck for DTCs.


      Body Electrical > Entry&Start > Trouble Codes
      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

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


    1. Reconnect the K28 steering lock ECU (steering lock actuator assembly) connector.

    2. Disconnect the K83 ID code box (immobiliser code ECU) connector.

    3. Clear the DTCs.

      Click here


      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

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    A

  4. CHECK DTC OUTPUT (POWER MANAGEMENT CONTOL ECU)


    1. Reconnect the K83 ID code box (immobiliser code ECU) connector.

    2. Disconnect the K33 power management control ECU connector.

    3. Clear the DTCs.

      Click here


      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 POWER MANAGEMENT CONTROL ECU Click here