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Home >> Subaru >> 2013 >> BRZ Limited, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 23 (Lin Communication System) >> Large-Scale Multiplex Communication System For Vehicle Body [LIN] >> DTC B2785: LIN Communication Error >> Inspection steps
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Inspection steps

WARNING: This page is about a different car, the 2018 Subaru BRZ. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: To replace the collation ECM (Smart key computer ASSY), the steering lock actuator ASSY, and the ID code box, refer to the procedure for engine immobilizer system registration.
  1. Clearing diagnostic code
    1. Clear the diagnostic code using the SSM4. (Refer to CHECKING/CLEARING DIAGNOSTIC CODES )
  2. DTC check
    1. Use SSM4 to check DTC output. (Refer to CHECKING/CLEARING DIAGNOSTIC CODES )
    RESULT DESCRIPTION

    Result Go to
    B2785 is output A
    B2785 is not output B

    B: Go to "How to simulate trouble phenomenon" (Refer to MALFUNCTION SYMPTOMS AND DTC CHECK )

    A: Go to next step

  3. Checking of the LIN communication line (Collation ECM (Smart key computer ASSY) - Steering lock actuator ASSY)
    1. Disconnect the connector D41 from the collation ECM (Smart key computer ASSY).
    2. Disconnect the connector D59 from the steering lock actuator ASSY.
    3. Disconnect the connector A30 from the ID code box (Immobilizer code ECM)*.
    4. Measure the resistance between the terminals.
      STANDARD VALUE RESISTANCE SPECIFICATION (OPEN CIRCUIT CHECK)

      Inspection terminals Inspection conditions Standard value
      D41-17 - D59-5 Always Less than 1 Ω
      D41-17 - A30-2* Always Less than 1 Ω
      STANDARD VALUE RESISTANCE SPECIFICATION (SHORT CIRCUIT CHECK)

      Inspection terminals Inspection conditions Standard value
      D41-17 - chassis ground Always 10 kΩ or more
      D59-5 - chassis ground Always 10 kΩ or more
      A30-2 - chassis ground* Always 10 kΩ or more
    5. Reconnect the connector D41 to the collation ECM (Smart key computer ASSY).

      *: with ID code box

      NG: Repair or replacement of wiring harness or connector

      OK: Go to next step

  4. DTC check (Steering lock actuator ASSY)
    1. Check DTC using SSM4. (Refer to CHECKING/CLEARING DIAGNOSTIC CODES )
      RESULT DESCRIPTION

      Result Go to
      B2785 is not output A
      B2785 is output B
    2. Reconnect the connector D59 to the steering lock actuator ASSY.

    B: Replacement of the collation ECM (Smart key computer ASSY)

    A: Go to next step

  5. Replacement of the steering lock actuator ASSY connector or ID code box (with ID code box)
    1. Replace the collation ECM (Smart key computer ASSY) or ID code box* with a new part.
    2. Clear the diagnostic code using the SSM4. (Refer to CHECKING/CLEARING DIAGNOSTIC CODES ) *: with ID code box
  6. Rechecking the diagnostic codes
    1. Using SSM4, check the diagnostic code again. (Refer to CHECKING/CLEARING DIAGNOSTIC CODES )
    RESULT DESCRIPTION

    Result Go to
    B2785 is not output A
    B2785 is output B

    B: Replacement of the collation ECM (Smart key computer ASSY)

    A: Go to next step

    Complete (Failure of the steering lock actuator ASSY connector or ID code box (with ID code box))

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