2009 Lexus SC 430FACTORY OEM SERVICE PROCEDURE

Diagnostic Trouble Code Chart

WARNING: This page is about a different car, the 2011 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  1. CERTIFICATION ECU DIAGNOSTIC TROUBLE CODE CHART 
    CERTIFICATION ECU

    DTC Code Detection Item Trouble Area Refer to
    B1242 Wireless Door Lock Tuner Circuit Malfunction 1. Tuner
    2. Wire harness
    3. Certification ECU    		 Refer to DTC B1242: Wireless Door Lock Tuner Circuit Malfunction
    B2784 Antenna Coil Open / Short 1. Engine switch
    2. Wire harness
    3. Certification ECU    		 Refer to DTC B2784: Antenna Coil Open / Short
    B2785 Communication Malfunction between ECUs Connected by LIN 1. Wire harness
    2. Steering lock actuator (Steering lock ECU)
    3. ID code box
    4. Power source control ECU
    5. Certification ECU    		 Refer to DTC B2785: Communication Malfunction between ECUs Connected by LIN
    B2786 No Response from Steering Lock ECU 1. Wire harness
    2. Steering lock actuator (Steering lock ECU)
    3. Certification ECU    		 Refer to DTC B2786: No Response from Steering Lock ECU
    B2789 No Response from ID BOX 1. Wire harness
    2. ID code box
    3. Certification ECU    		 Refer to DTC B2789: No Response from ID BOX
    B278A Short to GND in Immobilizer System Power Source Circuit 1. Wire harness
    2. Engine switch
    3. Certification ECU    		 Refer to DTC B278A: Short to GND in Immobilizer System Power Source Circuit
    B2790 ID BOX EEPROM Malfunction ID code box Refer to DTC B2790: ID BOX EEPROM Malfunction
  2. ECM DIAGNOSTIC TROUBLE CODE CHART 

    HINT: 

    The DTCs for the engine immobilizer system are specified above. If the other codes are output, check the DTC chart for the SFI system.

    ECM

    DTC Code Detection Item Trouble Area Refer to
    B2799 Engine Immobilizer System Malfunction 1. Wire harness
    2. ECM
    3. ID code box    		 Refer to DTC B2799: Engine Immobilizer System Malfunction
    B279A Theft Deterrent System Communication Line High Fixation 1. Wire harness
    2. ID code box
    3. ECM    		 Refer to DTC B279A: Theft Deterrent System Communication Line High Fixation
    B279C Theft Deterrent System Presence Detection ECM Refer to DTC B279C: Theft Deterrent System Presence Detection
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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