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Home >> Lexus >> 2019 >> LC 500 >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (Coupe) (4 Of 4) & Symptom Tests >> Electronically Controlled Brake System >> Brake Hold Standby Indicator Light Circuit [03/2017 - ] >> Procedure

Brake Hold Standby Indicator Light Circuit [03/2017 - ]: Procedure

  1. PRE-CHECK 
    1. If the brake hold standby indicator light does not illuminate even though the brake hold switch 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
      • SFI 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 [03/2017 - 06/2019] , or refer to DIAGNOSIS SYSTEM [06/2019 - 04/2020] , or refer to DIAGNOSIS SYSTEM [04/2020 - 11/2021] , or refer to DIAGNOSIS SYSTEM [11/2021 - 10/2022] , or refer to DIAGNOSIS SYSTEM [10/2022 - 05/2023] , or refer to DIAGNOSIS SYSTEM [05/2023 - ]

      Result

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

    Result: 

    INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 09/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2018 - 05/2023]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2023 - ] 

    Result: 

    See step  3

  3. PERFORM ACTIVE TEST USING TECHSTREAM (BRAKE HOLD STANDBY INDICATOR LIGHT) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Select the Active Test on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [03/2017 - 05/2023] , or refer to DATA LIST / ACTIVE TEST [05/2023 - ]

      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 > Active Test 

      Tester Display
      BH Standby Light
    4. Select the Data List on the Techstream.

      Refer to DATA LIST / ACTIVE TEST [03/2017 - 05/2023] , or refer to DATA LIST / ACTIVE TEST [05/2023 - ]

      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 > Data List 

      Tester Display
      BH Standby Light
    5. 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: 

    REPLACE SKID CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

    Result: 

    See step  4

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

      Refer to DATA LIST / ACTIVE TEST [03/2017 - ]

      Body Electrical > Combination Meter > Active Test 

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

      OK

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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - ] 

    Result: 

    OK 

    See step  5

  5. INSPECT BRAKE HOLD SWITCH 
    1. Turn the engine switch off.
      GTY811358Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Brake Hold Switch)
    2. Disconnect the P2 brake hold switch connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (+B) - 4 (E) Switch pushed Below 1 Ω
      3 (+B) - 4 (E) Switch not pushed 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE HOLD SWITCH. Refer to  REMOVAL [03/2017 - ] 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY - BRAKE HOLD SWITCH) 
    1. Disconnect the A10 skid control ECU assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A10-14 (HZRI) - P2-3 (+B) Always Below 1 Ω
      A10-14 (HZRI) or P2-3 (+B) - Body ground Always 10 kΩ or higher
      P2-4 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR BRAKE HOLD SWITCH 

    Result: 

    OK 

    See step  7

  7. INSPECT COURTESY LIGHT SWITCH 
    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. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - ] 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (CTY TERMINAL) 
    1. Measure the voltage and waveform according to the value(s) in the table below.
      GTY830177Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Skid Control ECU Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A8-14 (CTY) - Body ground Driver door open Below 1 V
      A8-14 (CTY) - Body ground Driver door closed Pulse generation (waveform 1)
      1. Waveform 1 (Reference)
        GTY428522Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        *a Driver door closed
        *b Driver door open
        Item Content
        Tester Connection A8-14 (CTY) - Body ground
        Tool Setting 5 V/DIV., 10 ms./DIV.
        Vehicle Condition Driver door closed → open

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023]  , or refer to  REMOVAL [05/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (CTY CIRCUIT)