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DTC P0504-2B: Brake Switch "A"/"B" Signal Cross Coupled [10/2015 - ]: Procedure

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  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY) 
    GTY631378Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Stop Light Switch Assembly)
    1. Disconnect the stop light switch assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A52-1 (B) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  2

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY) 
    GTY676660Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Stop Light Switch Assembly)
    1. Disconnect the stop light switch assembly connector.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A52-5 (B) - Body ground Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  3

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A52-3 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK TERMINAL VOLTAGE (STP AND ST1- VOLTAGE) 
    GTY685437Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Brake Pedal Depressed *b Brake Pedal Released
    *c Front view of wire harness connector
    (to ECM)    		 - -
    1. Disconnect the ECM connector.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Brake Pedal Operation Specified Condition
      A82-10 (ST1-) - Body ground Released 7.5 to 14 V
      Depressed Below 1.5 V
      A82-9 (STP) - Body ground Released Below 1.5 V
      Depressed 7.5 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [10/2015 - ] 

    Result: 

    NG 

    See step  5

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A52-4 (L) - A82-10 (ST1-) Always Below 1 Ω
      A52-2 (L) - A82-9 (STP) Always Below 1 Ω
      A52-4 (L) or A82-10 (ST1-) - Body ground and other terminals Always 10 kΩ or higher
      A52-2 (L) or A82-9 (STP) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - STOP LIGHT SWITCH ASSEMBLY) 
    1. Disconnect the semiconductor pwr integration ECU connector.
    2. Disconnect the 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
      2F-4 - A52-5 (B) Always Below 1 Ω
      2F-4 or A52-5 (B) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SEMICONDUCTOR PWR INTEGRATION ECU. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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