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Home >> Lexus >> 2021 >> GX 460 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (Diagnostic Codes) (4 Of 7) >> SFI System >> DTC P0504: Brake Switch "A" / "B" Correlation [08/2015 - 08/2019] >> Procedure

DTC P0504: Brake Switch "A" / "B" Correlation [08/2015 - 08/2019]: Procedure

  1. READ VALUE USING TECHSTREAM (STP SIGNAL AND ST1- VOLTAGE) 
    1. Connect the Techstream to the DLC3.
      GTY630978Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light Switch.
    5. Read the value displayed on the Techstream.

      Standard

      Condition Specified Condition
      Brake pedal depressed STP signal ON
      Brake pedal released STP signal OFF
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G44-8 (ST1-) - Body ground Brake pedal released 11 to 14 V
      Brake pedal depressed 0 to 3 V
      TEXT IN ILLUSTRATION

      *a Depressed
      *b Released
      *c Component with harness connected
      (ECM)

    Result: 

    OK 

    CHECK FOR INTERMITTENT PROBLEMS 

    (Refer to CHECK FOR INTERMITTENT PROBLEMS [08/2015 - ] )

    Result: 

    NG 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM) 
    1. Disconnect the A5 stop light switch assembly connector.
    2. Disconnect the G44 ECM connector.
    3. Disconnect the G45 ECM connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A5-2 (L) - G45-18 (STP) Always Below 1 Ω
      A5-4 (L) - G44-8 (ST1-)
      A5-2 (L) or G45-18 (STP) - Body ground 10 kΩ or higher
      A5-4 (L) or G44-8 (ST1-) - Body ground

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STOP LIGHT SWITCH) 

    Result: 

    OK 

    See step  3

  3. REPLACE STOP LIGHT SWITCH ASSEMBLY 
    1. Replace the stop light switch assembly (Refer to REMOVAL [08/2015 - ] ).

    Result: 

    NEXT 

    See step  4

  4. CHECK WHETHER DTC OUTPUT RECURS (P0504) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [08/2015 - ] ).
    5. Turn the engine switch off and wait for at least 30 seconds.
    6. Turn the engine switch on (IG).
    7. Turn the Techstream on.
    8. Depressed and released the brake pedal.
    9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    10. Read the pending DTCs.

      Result

      Result Proceed to
      DTC P0504 is output A
      DTC is not output B

    Result: 

    A 

    REPLACE ECM 

    (Refer to REMOVAL [08/2015 - ] )

    Result: 

    B 

    END 

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