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)

  • Transmission control ECU assembly

  • ID code box (immobiliser code ECU)

  • Wire harness or connector

  • P CON MAIN fuse

  • ECU-B NO. 2 fuse

  • AM2 fuse

WIRING DIAGRAM

A01KRTKE01

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, ID code box (immobiliser code ECU) or transmission control ECU assembly is replaced, refer to Service Bulletin.

PROCEDURE


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


    1. Disconnect the E116 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the A132 transmission control ECU assembly connector.

    3. Disconnect the E87 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
      E116-17 (LIN) - A132-24 (LIN) Always Below 1 Ω
      E116-17 (LIN) - E87-2 (LIN1) Always Below 1 Ω
      E116-17 (LIN) - Body ground Always 10 kΩ or higher
      A132-24 (LIN) - Body ground Always 10 kΩ or higher
      E87-2 (LIN1) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK DTC OUTPUT (TRANSMISSION CONTROL ECU ASSEMBLY)


    1. Reconnect the E116 certification ECU (smart key ECU assembly) connector.

    2. Reconnect the E87 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 TRANSMISSION CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE TRANSMISSION CONTROL ECU ASSEMBLY for RHD: Click here

    A

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


    1. Reconnect the A132 transmission control ECU assembly connector.

    2. Disconnect the E87 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

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)