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DTC B2785: Communication Malfunction between ECUs Connected by LIN: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - EACH ECU) 
    1. Disconnect the L62, L6, L10*1 and A24 connectors.
      • *1: for Canada
      Fig 1: Identifying Automatic Light Control System Connectors And Terminals
      GTY212722Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance and voltage according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L62-29 (LIN) - A24-24 (LIN) Always Below 1 Ω
      L62-29 (LIN) - L6-11 (LIN2) Always Below 1 Ω
      L62-29 (LIN) - L10-3 (LIN1)*1 Always Below 1 Ω
      L62-29 (LIN) - Body ground Always 10 kΩ or higher

      Standard Voltage

      Tester Connection Condition Specified Condition
      L62-29 (LIN) - Body ground Always Below 1 V
      • *1: for Canada
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Certification ECU (Smart Key ECU Assembly))      		 *2 Front view of wire harness connector
      (to ID code box (Immobilizer Code ECU))
      *3 Front view of wire harness connector
      (to Power Management Control ECU)      		 *4 Front view of wire harness connector
      (to Transmission Control ECU Assembly)
      *5 for Canada - -

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  2. CHECK DTC OUTPUT (TRANSMISSION CONTROL ECU ASSEMBLY) 
    1. Reconnect the L62, L6 and L10*1 connectors.
      • *1: for Canada
    2. Clear the DTC. Refer to DTC CHECK / CLEAR .
    3. Recheck for DTCs.

      Result

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

    B → See step   5 

    A: Go to next step 

  3. CHECK DTC OUTPUT (POWER MANAGEMENT CONTROL ECU) 
    1. Reconnect the A24 connector.
    2. Disconnect the L6 connector.
    3. Clear the DTC. Refer to DTC CHECK / CLEAR .
    4. Recheck for DTCs.

      Result

      Result Proceed to
      DTC B2785 is output (for Canada) A
      DTC B2785 is output (except Canada) B
      DTC B2785 is not output C

    B → See step   7 

    C → See step   8 

    A: Go to next step 

  4. CHECK DTC OUTPUT (ID CODE BOX (IMMOBILIZER CODE ECU)) 
    1. Reconnect the L6 connector.
    2. Disconnect the L10 connector.
    3. Clear the DTC. Refer to DTC CHECK / CLEAR .
    4. Recheck for DTCs.

      Result

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

    B → See step   6 

    A → See step   7 

  5. REPLACE TRANSMISSION CONTROL ECU ASSEMBLY. Refer to  REMOVAL 
  6. REPLACE ID CODE BOX (IMMOBILIZER CODE ECU). Refer to  REMOVAL 
  7. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL 
  8. REPLACE POWER MANAGEMENT CONTROL ECU. Refer to  REMOVAL 
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