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 and 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)

  • Transmission control ECU assembly

  • ID code box (immobiliser code ECU)

  • Wire harness or connector

WIRING DIAGRAM

A005AURE05
*a ID Code Box (Immobiliser Code ECU)
*b Certification ECU (Smart Key ECU Assembly)
*c Transmission Control ECU Assembly
*d LIN Communication Line

CAUTION / NOTICE / HINT

Note


  • If the certification ECU (smart key ECU assembly) is replaced, register the key.

  • If the transmission control ECU assembly is replaced, register the ECU code.

  • If the ID code box (immobiliser code ECU) is replaced, register the ECU code and ECU communication ID.

  • When using the GTS to troubleshoot with the power switch off:

    Connect the GTS to the DLC3, and turn the courtesy switch on and off at 1.5-second intervals until communication between the GTS and vehicle begins.

PROCEDURE


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


    1. Disconnect the L197, L191 and A24 connectors.

    2. Measure the resistance and voltage according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L197-17 (LIN) - A24-24 (LIN) Always Below 1 Ω
      L197-17 (LIN) - L191-2 (LIN1) Always Below 1 Ω
      L197-17 (LIN) - Body ground Always 10 kΩ or higher
      Standard Voltage
      Tester Connection Condition Specified Condition
      L197-17 (LIN) - Body ground Always Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK DTC OUTPUT (TRANSMISSION CONTROL ECU ASSEMBLY)


    1. Reconnect the L197 and L191 connectors.

    2. Clear the DTC Click here.

    3. Recheck for DTCs.

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

    B

    REPLACE TRANSMISSION CONTROL ECU ASSEMBLY Click here

    A

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


    1. Reconnect the A24 connector.

    2. Disconnect the L191 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

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    B

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU)