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DTC B2284: Brake Signal Malfunction [08/2019 - ]: Procedure

WARNING: This page is about a different car, the 2021 Toyota Tundra and 2020 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
  1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH1) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Power Source Control / Data List.
    5. Read the Data List according to the display on the Techstream.
      POWER SOURCE CONTROL

      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.

      OK

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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2017 - ] 

    Result: 

    NG 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) AND BODY GROUND) 
    1. Disconnect the J197 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the A4 stop light switch assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J197-2 (STP1) - A4-1 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. Reconnect the certification ECU (smart Key ECU assembly) connector.
    2. Reconnect the A4 stop light switch assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      Fig 1: Certification ECU Connector End View
      GTY843500Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))

      Standard Voltage

      Tester Connection Condition Specified Condition
      J197-2 (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 [08/2019 - ] 

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [08/2015 - ] 

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