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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (Except HV) - Diagnostic Codes (2 Of 3) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for Gasoline Model) >> DTC C0540-17: Brake Pressure Sensor "A" Circuit Voltage Above Threshold [12/2019 - ] >> Procedure

DTC C0540-17: Brake Pressure Sensor "A" Circuit Voltage Above Threshold [12/2019 - ]: Procedure

  1. CLEAR DTC 
    1. Clear the DTCs.

      Chassis > Brake/EPB > Clear DTCs 

    2. Turn the ignition switch off.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. RECONFIRM DTC 
    1. Based on the Freeze Frame Data and interview with the customer, attempt to reproduce the conditions when the malfunction occurred.
    2. Check if the same DTC is output.

      Chassis > Brake/EPB > Trouble Codes 

      Result

      Result Proceed to
      DTC C0540-17 is output A
      DTCs C0540-17 and P0571-13 are output B

    Result: 

    B 

    GO TO DTC CHART (P0571-13). Refer to  DTC P0571-13: Brake Switch "A" Circuit Open [12/2019 - ] 

    Result: 

    A 

    See step  3

  3. READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY) 
    1. Check that the stop light switch assembly condition observed on the GTS changes according to brake pedal operation.

      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

      OK

      The GTS displays OFF / ON according to brake pedal operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  4

  4. READ VALUE USING GTS (MASTER CYLINDER SENSOR) 
    1. Start the engine.
    2. Check the value of Data List item Master Cylinder Sensor 1 when the brake pedal is released.

      Chassis > Brake/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Master Cylinder Sensor 1 Master cylinder pressure sensor pressure (value detected by ECU) Min.: -1.00 MPa
      Max.: 23.99 MPa      		 Brake pedal released: -1.00 to 0.00 MPa Reading increases when brake pedal is depressed

      Chassis > Brake/EPB > Data List 

      Tester Display
      Master Cylinder Sensor 1

      OK

      The value of Data List item Master Cylinder 1 is within standard range.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ] 

    Result: 

    OK 

    See step  5

  5. CLEAR DTC 
    1. Clear the DTCs.

      Chassis > Brake/EPB > Clear DTCs 

    2. Turn the ignition switch off.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. RECONFIRM DTC 
    1. Based on the Freeze Frame Data and interview with the customer, attempt to reproduce the conditions when the malfunction occurred.
    2. Check if the same DTC is output.

      Chassis > Brake/EPB > Trouble Codes 

      Result

      Result Proceed to
      DTC C0540-17 is not output. A
      DTC C0540-17 is output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ] 

  7. CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION 
    1. Turn the ignition switch off.
    2. Check the stop light switch assembly installation.

      Refer to INSTALLATION [12/2019 - ]

      OK

      The stop light switch assembly installation are normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSTALL STOP LIGHT SWITCH ASSEMBLY CORRECTLY. Refer to  INSTALLATION [12/2019 - ] 

    Result: 

    OK 

    See step  8

  8. INSPECT STOP LIGHT SWITCH ASSEMBLY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    OK

    The stop light switch assembly is normal.

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      OK

      The connector is securely connected.

      GTY869147Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Actuator Assembly))
    2. Disconnect the A39 skid control ECU (brake actuator assembly) connector.
    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-11 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      A39-11 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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