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Home >> Toyota >> 2024 >> Land Cruiser First Edition >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (5 Of 5), Symptom Tests & Circuit Tests >> Electronically Controlled Brake System >> DTC P0571-13: Brake Switch "A" Circuit Open [02/2024 - ] >> Procedure

DTC P0571-13: Brake Switch "A" Circuit Open [02/2024 - ]: Procedure

  1. CHECK STOP LIGHT OPERATION 
    1. Check that the stop lights come on when the brake pedal is depressed.

      Result

      Result Proceed to
      All stop lights illuminate when the brake pedal is depressed and turn off when the brake pedal is released. A
      All stop lights do not illuminate when the brake pedal is depressed. B
      One or more stop lights illuminate when the brake pedal is depressed but remain on when the brake pedal is released. C

    Result: 

    B 

    See step  10

    Result: 

    C 

    See step  6

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY) 
    1. Check the value of Stop Light SW when the brake pedal is depressed.

      Chassis > Brake/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch assembly status
      (STP or STP2 terminal input)      		 OFF / ON OFF: Brake pedal released
      ON: Brake pedal depressed      		 HINT: 
      • Stop light control relay off: STP terminal status displayed.
      • Stop light control relay on: STP2 terminal status displayed.

      Chassis > Brake/EPB > Data List 

      Tester Display
      Stop Light SW

      Result

      Result Proceed to
      The value of Stop Light SW is ON A
      None of the above conditions are met B

    Result: 

    B 

    See step  9

    Result: 

    A 

    See step  3

  3. STOP LIGHT SWITCH ASSEMBLY OUTPUT CIRCUIT INSPECTION 

    Pre-procedure1

    1. Turn the ignition switch off.

      Procedure1

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

      Pre-procedure2

    3. Turn the ignition switch to ON.

      Procedure2

    4. Measure the voltage according to the value(s) in the table below.
      GTY1222472Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Stop Light Switch Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A44-1 (OUT) - Body ground
      • Ignition switch ON
      • The headlights are on
      • The blower motor switch is in the HI position
      • The rear window defogger is turned on
      • Stop light switch assembly off (Brake pedal released)
      		 Below 1.5 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. None

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CLEAR DTC 

    Pre-procedure1

    1. None

      Procedure1

    2. Clear the DTCs.

      Chassis > Brake/EPB > Clear DTCs 

      Result

      Proceed to
      NEXT

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    NEXT 

    See step  5

  5. RECONFIRM DTC 

    Pre-procedure1

    1. Based on the Freeze Frame Data and interview with the customer, attempt to reproduce the conditions when the malfunction occurred.

      Procedure1

    2. Check if the same DTC is output.

      Chassis > Brake/EPB > Trouble Codes 

      Result

      Result Proceed to
      P0571-13 is not output A
      P0571-13 is output B

      Post-procedure1

    3. None

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [02/2024 - ]

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY 

    Refer to REMOVAL [02/2024 - ]

  6. CHECK STOP LIGHT SWITCH ASSEMBLY 

    Pre-procedure1

    1. Turn the ignition switch off.

      Procedure1

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

      Pre-procedure2

    3. Disconnect the A44 stop light switch assembly connector.

      Procedure2

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A44-1 (OUT) - Body ground Stop light switch assembly off
      (Brake pedal released)      		 Below 1.5 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    6. None

    Result: 

    OK 

    REPLACE STOP LIGHT SWITCH ASSEMBLY 

    Refer to REMOVAL [02/2024 - ]

    Result: 

    NG 

    See step  7

  7. CHECK BRAKE ACTUATOR ASSEMBLY 

    Procedure1

    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

      Pre-procedure1

    2. Disconnect the A49 No. 2 skid control ECU (brake actuator assembly) connector.

      Procedure2

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A44-1 (OUT) - Body ground Stop light switch assembly off
      (Brake pedal released)      		 Below 1.5 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. None

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY 

    Refer to REMOVAL [02/2024 - ]

    Result: 

    NG 

    See step  8

  8. CHECK FOR SHORT TO +B IN STP CIRCUIT 
    1. Check that there is no short to +B in the STP circuit (wire harnesses, connectors, ECUs and stop lights).

      OK

      No short to +B.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [02/2024 - ]

    Result: 

    NG 

    REPAIR OR REPLACE MALFUNCTIONING PART 

  9. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 

    Pre-procedure1

    1. Turn the ignition switch off.

      Procedure1

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

      Pre-procedure2

    3. Disconnect the A49 No. 2 skid control ECU (brake actuator assembly) connector.

      Procedure2

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A49-11 (STP) - Body ground Stop light switch assembly on
      (Brake pedal depressed)      		 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    6. None

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY 

    Refer to REMOVAL [02/2024 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  10. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - STOP LIGHT) 
    1. Check that there is no open in the wire harnesses and connectors from terminal OUT of the stop light switch assembly to the stop lights.

      OK

      No open.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY 

    Refer to REMOVAL [02/2024 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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