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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 9 (Electronically Controlled Brake System (Diagnostic Codes (4 Of 4) & Circuit Tests) (Hybrid)) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model) >> Brake Hold Standby Indicator Light Circuit [10/2018 - ] >> Procedure

Brake Hold Standby Indicator Light Circuit [10/2018 - ]: Procedure

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  1. PRE-CHECK 
    1. If the brake hold standby indicator light does not illuminate even though the brake hold switch (combination switch assembly) is pushed, check that the brake hold function operation conditions are met.
      1. The driver side door is closed.
      2. The driver side seat belt is fastened.
      3. The system is normal.

      HINT: 

      If a malfunction occurs in one of the following systems, the brake hold operated indicator light will blink. If this occurs, perform troubleshooting on the malfunctioning system.

      • Brake system
      • Electric parking brake system
      • Hybrid control system

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK CAN COMMUNICATION SYSTEM 
    1. Check if CAN communication system DTCs are output.

      Refer to DIAGNOSIS SYSTEM [10/2018 - 10/2019] , or refer to DIAGNOSIS SYSTEM [10/2019 - 08/2021] , or refer to DIAGNOSIS SYSTEM [08/2021 - 07/2022] , or refer to DIAGNOSIS SYSTEM [07/2022 - ]

      Result

      Result Proceed to
      DTCs are not output. A
      DTCs are output. B

    Result: 

    B 

    INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - ] 

    Result: 

    A 

    See step  3

  3. CHECK IF BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY CONNECTOR IS SECURELY CONNECTED 
    1. Check if the skid control ECU (brake booster with master cylinder assembly) connector is securely connected.

      OK

      The connector is securely connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTOR TO BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY CORRECTLY 

    Result: 

    OK 

    See step  4

  4. INSPECT COMBINATION METER ASSEMBLY 
    1. Turn the power switch off.
    2. Perform the Active Test of the combination meter assembly (meter CPU) using the Techstream.

      Refer to DATA LIST / ACTIVE TEST [10/2018 - 07/2022] , or refer to DATA LIST / ACTIVE TEST [07/2022 - ]

      Body Electrical > Combination Meter > Active Test 

      Tester Display
      Brake Hold Indicator
    3. Check the combination meter assembly.

      OK

      The brake hold standby indicator light turns on or off in accordance with Techstream operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - 07/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [07/2022 - ] 

    Result: 

    OK 

    See step  5

  5. PERFORM ACTIVE TEST USING TECHSTREAM (BH STANDBY LIGHT) 
    1. Select the Active Test on the Techstream.

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

      Chassis > ABS/VSC/TRAC > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      BH Standby Light Brake hold standby indicator light Indicator light ON/OFF Observe combination meter assembly

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      BH Standby Light Brake hold standby indicator light ON or OFF ON: Indicator light on
      OFF: Indicator light off      		 -

      Chassis > ABS/VSC/TRAC > Active Test 

      Active Test Display
      BH Standby Light
      Data List Display
      BH Standby Light
    2. Check the operating condition of the brake hold standby indicator light when operating it using the Techstream.

      Result

      Result Proceed to
      Brake hold standby indicator light in the Data List does not change using the Active Test. A
      Brake hold standby indicator light in the Data List turns ON/OFF using the Active Test. B

    Result: 

    A 

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

    Result: 

    B 

    See step  6

  6. INSPECT COMBINATION SWITCH ASSEMBLY 
    1. Turn the power switch off.
      GTY821811Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Brake Hold Switch (Combination 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. Disconnect the F34 brake hold switch (combination switch assembly) connector.
    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (+B) - 5 (E) Switch pushed Below 1 Ω
      1 (+B) - 5 (E) Switch not pushed 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - COMBINATION SWITCH 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.
    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A37-20 (CSW2) - F34-1 (+B) Always Below 1 Ω
      A37-20 (CSW2) or F34-1 (+B) - Body ground Always 10 kΩ or higher
      F34-5 (E) - 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. INSPECT FRONT DOOR COURTESY LIGHT SWITCH ASSEMBLY LH 
    1. Turn on the interior lights and check that they illuminate, and then set the switch so that the lights illuminate when the door is opened.
    2. Check that the lights illuminate when the driver side door is opened.

      OK

      The interior lights illuminate when the driver side door is opened.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT LIGHTING SYSTEM (COURTESY LIGHT SWITCH CIRCUIT). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - 07/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [07/2022 - ] 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (CTY TERMINAL) 
    1. Measure the voltage according to the value(s) in the table below.
      GTY795744Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

      Standard Voltage

      Tester Connection Condition Specified Condition
      A37-24 (CTY) - Body ground Driver door open Below 1.5 V
      A37-24 (CTY) - Body ground Driver door closed 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 (CTY CIRCUIT) 

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