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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Body & Frame >> Door Locks >> Smart Key System (For Start, Except HV) - Diagnostic Codes (1 Of 2) >> SMART KEY SYSTEM (for Start Function, Gasoline Model) >> DTC B2284: Brake Signal Malfunction [12/2019 - 10/2022] >> Procedure

DTC B2284: Brake Signal Malfunction [12/2019 - 10/2022]: Procedure

  1. READ VALUE USING GTS (STOP LIGHT SWITCH1) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light Switch1 State of brake pedal OFF or ON OFF: Brake pedal released
      ON: Brake pedal depressed
      • Use this item to determine if the stop light switch assembly is malfunctioning.
      • The engine cannot be started when this item is OFF.
      • If the stop light switch assembly is malfunctioning, the engine can be started by pressing and holding the engine switch for a certain period of time.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Stop Light Switch1

      OK

      The GTS display changes correctly in response to the brake pedal operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STOP LIGHT SWITCH ASSEMBLY) 
    1. Disconnect the M5 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the A42 stop light switch assembly connector.
    3. Disconnect the A28 ECM connector.
    4. Disconnect the A39 skid control ECU (brake actuator assembly) connector.
    5. Disconnect the H28 shift lock control unit assembly connector.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M5-25 (STP1) - A42-3 (L) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 
    1. Connect the M5 certification ECU (smart key ECU assembly) connector.
    2. Connect the A42 stop light switch assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY903816Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))

      Standard Voltage

      Tester Connection Condition Specified Condition
      M5-25 (STP1) - Body ground Brake pedal released → depressed 1 V or less → 9 V or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

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