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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (2GR-FKS) - Diagnostic Codes (4 Of 6) >> SFI System >> DTC P0504-2B: Brake Switch "A"/"B" Signal Cross Coupled [12/2019 - 10/2022] >> Procedure

DTC P0504-2B: Brake Switch "A"/"B" Signal Cross Coupled [12/2019 - 10/2022]: Procedure

  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY) 
    GTY864917Courtesy 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
      A42-7 (B) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  2

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY) 
    GTY864916Courtesy 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 ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A42-6 (B) - Body ground Ignition switch ON 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
      A42-2 (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) 
    GTY924456Courtesy 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 ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Brake Pedal Operation Specified Condition
      A28-42 (ST1-) - Body ground Released 7.5 to 14 V
      Depressed Below 1.5 V
      A28-27 (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 [12/2019 - 09/2020]  , or refer to  REMOVAL [09/2020 - 10/2022] 

    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
      A42-5 (L) - A28-42 (ST1-) Always Below 1 Ω
      A42-3 (L) - A28-27 (STP) Always Below 1 Ω
      A42-5 (L) or A28-42 (ST1-) - Body ground and other terminals Always 10 kΩ or higher
      A42-3 (L) or A28-27 (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 [12/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY) 
    1. Disconnect the instrument panel junction block assembly 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
      4C-15 - A42-6 (B) Always Below 1 Ω
      4C-15 or A42-6 (B) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND) 
    1. Disconnect the instrument panel junction block assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      4B-3 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (POWER SOURCE) 
    GTY839639Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Instrument Panel Junction Block Assembly)
    1. Disconnect the instrument panel junction block assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      4E-1 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Disconnect the instrument panel junction block assembly connector.
    2. Disconnect the certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      4A-17 - H48-17 (IG1D) Always Below 1 Ω
      4A-17 or H48-17 (IG1D) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK SMART KEY SYSTEM 
    1. Check the smart key system.

      Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 11/2023]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    NG 

    REPAIR SMART KEY SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 11/2023] 

  11. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - STOP LIGHT SWITCH ASSEMBLY) 
    1. Disconnect the instrument panel junction block assembly 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
      4C-3 - A42-7 (B) Always Below 1 Ω
      4C-3 or A42-7 (B) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (POWER SOURCE) 
    GTY839638Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Instrument Panel Junction Block Assembly)
    1. Disconnect the instrument panel junction block assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      4E-1 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) 

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