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)

  • Hybrid vehicle control ECU

  • ID code box (immobiliser code ECU)

  • Wire harness or connector

  • ECU-B NO. 1 fuse

  • ECU-B NO. 2 fuse

  • AM2 fuse

WIRING DIAGRAM

A003JYOE09

CAUTION / NOTICE / HINT

Note


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

  • Before replacing the certification ECU (smart key ECU assembly), hybrid vehicle control ECU or ID code box (immobiliser code ECU), refer to Service Bulletin.

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

    Click here

PROCEDURE


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


    1. Disconnect the I1 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the I3 hybrid vehicle control ECU 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.

      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 180 seconds or more without operating any switches.

      Standard Resistance
      Tester Connection Condition Specified Condition
      I1-13 (LIN) - I3-31 (LIN) Power switch off Below 1 Ω
      I1-13 (LIN) - I20-2 (LIN1) Power switch off Below 1 Ω
      I1-13 (LIN) or I20-2 (LIN1) - Body ground Power switch off 10 kΩ or higher
      I3-31 (LIN) or I20-2 (LIN1) - 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 (HYBRID VEHICLE CONTROL ECU)


    1. Reconnect the I1 certification ECU (smart key ECU assembly) connector.

    2. Reconnect the I20 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 HYBRID VEHICLE CONTROL ECU Click here

    A

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


    1. Reconnect the I3 hybrid vehicle control ECU connector.

    2. Disconnect the I20 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)