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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 33 (Electronically Controlled Brake System (Diagnostic Codes) (3 Of 4) (Hybrid)) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model) >> DTC C1425: Open in Stop Switch Circuit; DTC P0573: Brake Switch "A" Circuit High [10/2018 - ] >> Procedure

DTC C1425: Open in Stop Switch Circuit; DTC P0573: Brake Switch "A" Circuit High [10/2018 - ]: Procedure

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  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 TECHSTREAM (STOP LIGHT SW) 
    1. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [10/2018 - ]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch assembly ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released      		 -

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      Stop Light SW
    2. Check the value of Stop Light SW when the brake pedal is depressed.

      Result

      Result Proceed to
      The value of Stop Light SW is ON. A
      Other than above. B

    Result: 

    B 

    See step  9

    Result: 

    A 

    See step  3

  3. STOP LIGHT SWITCH ASSEMBLY OUTPUT CIRCUIT INSPECTION 
    1. Turn the power switch off.
      GTY968513Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Stop Light Switch Assembly)
    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.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A42-1 (ESS) - Body ground
      • Power switch on (IG)
      • 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)
      		 1.5 V or less

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CLEAR DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2018 - ]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. RECONFIRM DTC 
    1. Turn the power switch off.
    2. Turn the power switch on (READY).
    3. Perform a road test.
    4. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [10/2018 - ]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1425 and P0573 are not output. A
      DTCs C1425 and/or P0573 are output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - ] 

    Result: 

    B 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

  6. CHECK STOP LIGHT SWITCH ASSEMBLY 
    1. Turn the power switch off.
    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.

    3. Disconnect the A42 stop light switch assembly connector.
      GTY968486Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Stop Light Switch Assembly)
    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A42-1 (ESS) - Body ground Stop light switch assembly off
      (Brake pedal released)      		 1.5 V or less

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    NG 

    See step  7

  7. CHECK BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY 
    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.

    2. Disconnect the A37 skid control ECU (brake booster with master cylinder assembly) connector.
      GTY968486Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Stop Light Switch Assembly)
    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
      A42-1 (ESS) - Body ground Stop light switch assembly off
      (Brake pedal released)      		 1.5 V or less

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

    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 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 [10/2018 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE MALFUNCTIONING PART 

  9. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Turn the power switch off.
      GTY795754Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))
    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.

    3. Disconnect the A37 skid control ECU (brake booster with master cylinder assembly) connector.
    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A37-12 (STP) - Body ground Stop light switch assembly on
      (Brake pedal depressed)      		 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

  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 ESS of the stop light switch assembly to the stop lights.

      OK

      No open.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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