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HOMESERVICE MANUALSLEXUS2010LS 460L AWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTCOMMUNICATION DEVICESLIN COMMUNICATION (DIAGNOSTIC CODES & CIRCUIT TESTS)LIN COMMUNICATION SYSTEMDTC B2789: NO RESPONSE FROM ID BOXPROCEDURE
2010 Lexus LS 460L AWD

DTC B2789: No Response from ID BOX: Procedure

2010 Lexus LS 460L AWDSECTION Procedure
  1. CLEAR DTC 
    1. Clear the DTC. Refer to DTC CHECK / CLEAR .

    NEXT: Go to next step 

  2. CHECK FOR DTC 
    1. Recheck for DTC. Refer to DTC CHECK / CLEAR .

      OK

      DTC B2789 is not output.

    NG → See step   3 

    OK → See step   7 

  3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ID CODE BOX) 
    1. Disconnect the L15 ECU connector.
      Fig 1: Identifying Certification ECU And ID Code Box ECU Connectors L15 & L32
      GTY288813Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the L32 box connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      L15-10 (LIN) - L32-3 (LIN1) Always Below 1 Ω
      L15-10 (LIN) or L32-3 (LIN1) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. CHECK ID CODE BOX (BATTERY VOLTAGE AND GROUND) 
    1. Disconnect the L32 box connector.
      Fig 2: Identifying Terminals Of L32 Box Connector
      GTY140792Courtesy 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
      L32-8 (GND) - Body ground Always Below 1 Ω

      Standard voltage

      Tester Connection Condition Specified Condition
      L32-1 (+B) - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. REPLACE ID CODE BOX (IMMOBILIZER CODE ECU) 
    1. Temporarily replace the ID code box (immobilizer code ECU) with a new one. Refer to REMOVAL .
    2. Clear the DTC. Refer to DTC CHECK / CLEAR .

    NEXT: Go to next step 

  6. CHECK FOR DTC 
    1. Recheck for DTC. Refer to DTC CHECK / CLEAR .

      OK

      DTC B2789 is not output.

    NG → See step   8 

    OK → END (ID CODE BOX IS DEFECTIVE) 

  7. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  8. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL 
RENDER: 1.0x

NO RELATED

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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.