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Home >> Lexus >> 2021 >> LS 500 Base, AWD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (W/ Vacuum Brake Booster) - Diagnostic Codes (4 Of 4) & Symptom Tests >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster) >> Slip Indicator Light Remains ON [12/2017 - 09/2018] >> Procedure

Slip Indicator Light Remains ON [12/2017 - 09/2018]: Procedure

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

      Refer to DIAGNOSIS SYSTEM [12/2017 - 09/2018]

      Result

      Proceed to
      DTC is not output
      DTC is output

    Result: 

    DTC is output 

    CHECK CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018] 

    Result: 

    DTC is not output 

    See step  2

  2. CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED 
    1. Check if the skid control ECU (brake actuator assembly) connector is securely connected.

      OK

      The connector is securely connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTOR TO ECU CORRECTLY 

    Result: 

    OK 

    See step  3

  3. INSPECT BATTERY 
    1. Check the battery voltage.

      Standard voltage

      11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY. Refer to  ON-VEHICLE INSPECTION [12/2017 - 10/2020] 

    Result: 

    OK 

    See step  4

  4. CHECK TERMINAL VOLTAGE (IG1 TERMINAL) 
    1. Disconnect the A9 skid control ECU (brake actuator assembly) connector.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A9-12 (IG1) - Body ground Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT) 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL) 
    1. Turn the engine switch off.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A9-25 (GND1) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) 

    Result: 

    OK 

    See step  6

  6. READ VALUE USING TECHSTREAM (SLIP INDICATOR LIGHT) 
    1. Reconnect the A9 skid control ECU (brake actuator assembly) connector.
    2. Connect the Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.
    6. According to the display on the Techstream, read the Data List.

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Slip Indicator Light SLIP indicator light OFF or ON OFF: Indicator light off
      ON: Indicator light on
      -

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      Slip Indicator Light
    7. Check the Techstream display condition of the slip indicator light.

      Result

      Proceed to
      Display of the Data List remains OFF
      Display of the Data List remains ON

    Result: 

    Display of the Data List remains OFF 

    INSPECT METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 10/2023] 

    Result: 

    Display of the Data List remains ON 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018]