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Home >> Lexus >> 2006 >> IS 250 RWD, Automatic >> Repair and Diagnosis (Single Page) >> Body & Frame >> Door Locks >> Engine Immobilizer >> Engine Immobilizer System >> DTC B2785, B2786, B2789: Communication Malfunction between ECUs Connected by LIN; No Response from Steering Lock ECU; No Response from ID BOX >> Inspection Procedure

Inspection Procedure

  1. CHECK HARNESS AND CONNECTOR (LIN COMMUNICATION LINE AND BODY GROUND) 
    1. Disconnect the P33, J29, J55 and J69 ECU connectors.
      Fig 1: Identifying P33, J29, J55 & J69 ECU Connectors
      G04049172Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in TERMINAL CONNECTION SPECIFIED CONDITION TABLE  .

    Standard resistance 

    TERMINAL CONNECTION SPECIFIED CONDITION TABLE

    Tester Connection Condition Specified Condition
    P33-10 (LIN) - J69-3 (LIN1) Always Below 1 ohms
    P33-10 (LIN) - J55-30 (LIN1) Always Below 1 ohms
    P33-10 (LIN) -J29-5 (LIN) Always Below 1 ohms
    P33-10 (LIN) - Body ground Always 10 K ohms or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  2. CHECK DTC OUTPUT 
    1. Delete the DTCs (See DTC CHECK/CLEAR  ).
    2. Recheck for DTCs (See DTC CHECK/CLEAR  ).

    Result 

    RESULT TABLE

    Result Proceed to
    B2785 and B2786 outputs reoccur A
    B2785 and B2789 outputs reoccur B
    B2785 output reoccurs C

    B: Go to step   6 

    C: Go to step   10 

    A: Go to next step 

  3. REPLACE STEERING LOCK ECU 
    1. Replace the steering lock ECU.
  4. ECU CODE REGISTRATION 
    1. Register the ECU communication ID between the ECUs connected by LIN communication (See REGISTRATION  ).
  5. CHECK DTC OUTPUT 
    1. Check for DTCs (See DTC CHECK/CLEAR  ).

    Result 

    RESULT TABLE

    Result Proceed to
    B2785 and B2786 outputs reoccur A
    B2785 and B2786 outputs do not reoccur B

    B: END 

    A: REPLACE CERTIFICATION ECU 

  6. REPLACE ID CODE BOX 
  7. ELECTRICAL KEY REGISTRATION 
    1. Register the electrical key code in the certification ECU (See REGISTRATION  ).
  8. ECU COMMUNICATION ID REGISTRATION 
    1. Register the ECU communication ID between the ID code box and ECM (See REGISTRATION  ).
  9. CHECK DTC OUTPUT 
    1. Check for DTCs (See DTC CHECK/CLEAR  ).

    Result 

    RESULT TABLE

    Result Proceed to
    B2785 and B2789 outputs reoccurs A
    B2785 and B2789 outputs do not reoccur B

    B: END 

    A: REPLACE CERTIFICATION ECU 

  10. REPLACE CERTIFICATION ECU 
    1. Replace the certification ECU.
  11. ELECTRICAL KEY REGISTRATION 
    1. Register the electrical key code in the certification ECU (See REGISTRATION  ).
  12. ECU COMMUNICATION ID REGISTRATION 
    1. Register the ECU communication ID between the ID code box and ECM (See REGISTRATION  ).
  13. CHECK DTC OUTPUT 
    1. Check for DTCs (See DTC CHECK/CLEAR  ).

    Result 

    RESULT TABLE

    Result Proceed to
    B2785 output reoccurs A
    B2785 output does not reoccur B

    B: END 

    A: REPLACE POWER SOURCE CONTROL ECU 

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