Immobilizer System does not Operate Properly [10/2021 - 10/2022]: Procedure

2025 Toyota Highlander XLE, FWDSECTION Procedure
  1. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Smart Key > Trouble Codes 

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTCs are output B

    Result: 

    GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2021 - 10/2022] 

    Result: 

    See step  2

  2. READ VALUE USING GTS (IMMOBILIZER FUEL CUT STATUS) 
    1. Read the Data List according to the display on the GTS.

      Powertrain > Engine > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Immobilizer Fuel Cut Status Status of immobilizer fuel cut OFF or ON - -

      Powertrain > Engine > Data List 

      Tester Display
      Immobilizer Fuel Cut Status

      OK

      OFF is displayed after the engine is started.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO SFI SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2022] 

    Result: 

    NG 

    See step  3

  3. CHECK WHETHER ENGINE STARTS 
    1. Check that the engine starts 5 seconds after the ignition switch turned to ON.

      OK

      Engine starts normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    NG 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILIZER CODE ECU) - ECM) 
    1. Disconnect the H53 ID code box (immobilizer code ECU) connector.
    2. Disconnect the A28 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H53-3 (EFII) - A28-45 (IMO) Always Below 1 Ω
      H53-4 (EFIO) - A28-59 (IMI) Always Below 1 Ω
      H53-3 (EFII) or A28-45 (IMO) - Other terminals and body ground Always 10 kΩ or higher
      H53-4 (EFIO) or A28-59 (IMI) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK ECM (TERMINAL EFIO AND EFII) 
    1. Connect the H53 ID code box (immobilizer code ECU) connector.
    2. Connect the A28 ECM connector.
    3. Using an oscilloscope, check the waveform.
      GTY1105169Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (ID Code Box (Immobilizer Code ECU))
      *b Approximately 160 ms.
      *c Approximately 270 ms. *d Approximately 40 ms.
      *e Approximately 60 ms. *f Waveform (EFII)
      *g Waveform (EFIO) *h Waveform A
      *i Waveform B *j Waveform C
      *k Waveform A (detail) - -
      NOTE:

      The waveform shown in the illustration is an example for reference only. Noise, chattering, etc. are not shown.

      OK

      Tester Connection Condition Tool Setting Specified Condition
      H53-3 (EFII) - Body ground Within 3 seconds of engine start or within 3 seconds of ignition switch turned to ON after battery cable disconnected and reconnected 2 V/DIV., 500 ms./DIV. Pulse generation
      (See waveform (EFII))
      H53-4 (EFIO) - Body ground Within 3 seconds of engine start or within 3 seconds of ignition switch turned to ON after battery cable disconnected and reconnected 2 V/DIV., 500 ms./DIV. Pulse generation
      (See waveform (EFIO))

      Result

      Result Proceed to
      Normal waveform A
      Waveform A or C not output, or has abnormal wavelength or shape B
      Waveform B not output, or has abnormal wavelength or shape C

    Result: 

    REPLACE ID CODE BOX (IMMOBILIZER CODE ECU). Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    REPLACE ECM. Refer to  REMOVAL [09/2020 - 10/2022] 

    Result: 

    See step  6

  6. REGISTER ECU COMMUNICATION ID 
    1. Register the ECU communication ID.

      HINT: 

      Refer to Registration.

      Refer to REGISTRATION [10/2021 - 10/2022]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. CHECK WHETHER ENGINE STARTS 
    1. Check that the engine starts.

      OK

      Engine starts normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (COMMUNICATION ID REGISTRATION WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE ID CODE BOX (IMMOBILIZER CODE ECU). Refer to  REMOVAL [12/2019 - 10/2022] 

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.