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Home >> Lexus >> 2024 >> GX 550 Overtrail >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (2 Of 2) & Symptom Tests >> Electronically Controlled Brake System >> VSC OFF Switch Circuit [12/2023 - ] >> Procedure

VSC OFF Switch Circuit [12/2023 - ]: Procedure

  1. READ VALUE USING GTS (TRC (TRAC)/VSC OFF MODE) 
    1. Operate the GTS to check the Data List.

      Chassis > Brake/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      TRC (TRAC)/VSC OFF Mode TRAC/VSC off mode Normal mode (TRC (TRAC) ON/VSC ON) / TRC (TRAC) OFF mode (TRC (TRAC) OFF/VSC ON) / VSC expert mode (VSC expert mode MID ON) / VSC OFF mode (TRC (TRAC) OFF/VSC OFF) Normal mode (TRC (TRAC) ON/VSC ON): Normal mode
      TRC (TRAC) OFF mode (TRC (TRAC) OFF/VSC ON): TRAC off mode
      VSC OFF mode (TRC (TRAC) OFF/VSC OFF): VSC off mode
      -

      Chassis > Brake/EPB > Data List 

      Tester Display
      TRC (TRAC)/VSC OFF Mode
    2. Check that the indicator light and mode condition on the GTS change according to VSC OFF switch (No. 4 combination switch assembly) operation.

      Standard

      Switch Operation Mode Condition Display Multi-information Display (TRAC OFF Message) VSC OFF Indicator Light
      Not pressed Normal mode (TRC (TRAC) ON/VSC ON) Not displayed Does not come on
      Pressing the VSC OFF switch (No. 4 combination switch assembly) TRC (TRAC) OFF mode (TRC (TRAC) OFF/VSC ON) Displayed Does not come on
      Pressing and holding the VSC OFF switch (No. 4 combination switch assembly) VSC OFF mode (TRC (TRAC) OFF/VSC OFF) Displayed Comes on

      Result

      Result Proceed to
      Indicator light and mode condition display do not change. A
      Mode condition display is normal, but indicator light does not change. B
      Indicator light and mode condition display are normal. C

    Result: 

    INSPECT METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2023 - ] 

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2023 - ] 

    Result: 

    See step  2

  2. INSPECT NO. 4 COMBINATION SWITCH ASSEMBLY 

    Refer to INSPECTION [12/2023 - ]

    OK

    The VSC OFF switch (No. 4 combination switch assembly) operates normally.

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE NO. 4 COMBINATION SWITCH ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - NO. 4 COMBINATION SWITCH ASSEMBLY) 
    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.

    2. Disconnect the A25 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 resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P1-5 (+) - A25-9 (CSW) Always Below 1 Ω
      P1-5 (+) or A25-9 (CSW) - Body ground Always 10 kΩ or higher
      P1-12 (E) - Body ground 1 minute or more after disconnecting the cable from the negative (-) battery terminal Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR