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Home >> Lexus >> 2018 >> LS 500 Base, AWD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (W/ Vacuum Brake Booster) - Diagnostic Codes (1 Of 4) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster) >> DTC C0500-1F: Left Front Wheel Speed Sensor Circuit Intermittent; DTC C0506-1F: Right Front Wheel Speed Sensor Circuit Intermittent [09/2018 - 10/2023] >> Procedure

DTC C0500-1F: Left Front Wheel Speed Sensor Circuit Intermittent; DTC C0506-1F: Right Front Wheel Speed Sensor Circuit Intermittent [09/2018 - 10/2023]: Procedure

  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION) 
    1. Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to a DTC.

      Refer to CHECK FOR INTERMITTENT PROBLEMS [09/2018 - 10/2023]

      Chassis > Brake > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FR Speed Sensor Voltage Open Front speed sensor RH voltage open detection Under intermittent / Normal Under intermittent: Momentary interruption detected
      Normal: Momentary interruption not detected      		 After a momentary interruption occurs, if there is no momentary interruption for 1 second, it switches from "Under intermittent" to "Normal".
      FL Speed Sensor Voltage Open Front speed sensor LH voltage open detection Under intermittent / Normal Under intermittent: Momentary interruption detected
      Normal: Momentary interruption not detected      		 After a momentary interruption occurs, if there is no momentary interruption for 1 second, it switches from "Under intermittent" to "Normal".

      Chassis > Brake > Data List 

      Tester Display
      FR Speed Sensor Voltage Open
      FL Speed Sensor Voltage Open

      OK

      Normal (There are no momentary interruptions.)

      HINT: 

      Perform the above inspection before removing the sensor and connector.

      Result

      Proceed to
      OK
      NG (for 2WD)
      NG (for AWD)

    Result: 

    NG (for 2WD) 

    See step  4

    Result: 

    NG (for AWD) 

    See step  8

    Result: 

    OK 

    See step  2

  2. READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR) 
    1. Turn the engine switch off.
    2. Connect the Techstream to the DLC3.
    3. Start the engine.
    4. Select the Data List using the Techstream.

      Refer to DATA LIST / ACTIVE TEST [09/2018 - 10/2023]

      Chassis > Brake > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FR Wheel Speed Front wheel speed sensor RH reading Min.: 0.0 km/h (0.0 mph)
      Max.: 6553.5 km/h (4072 mph)      		 Vehicle stopped: 0.0 km/h (0.0 mph) When driving at constant speed: No large fluctuations
      FL Wheel Speed Front wheel speed sensor LH reading Min.: 0.0 km/h (0.0 mph)
      Max.: 6553.5 km/h (4072 mph)      		 Vehicle stopped: 0.0 km/h (0.0 mph) When driving at constant speed: No large fluctuations

      Chassis > Brake > Data List 

      Tester Display
      FR Wheel Speed
      FL Wheel Speed
    5. Check the speed value output from the speed sensor displayed on the Techstream.

      HINT: 

      Factors that affect the indicated vehicle speed include tire size, tire pressure, and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, see the reference chart.

      Refer to OPERATION CHECK [12/2017 - 10/2020] , or refer to OPERATION CHECK [10/2020 - 10/2023]

      OK

      The speed value output from the speed sensor displayed on the Techstream is similar to the speed indicated on the speedometer.

      Result

      Proceed to
      OK
      NG (for 2WD)
      NG (for AWD)

    Result: 

    NG (for 2WD) 

    See step  4

    Result: 

    NG (for AWD) 

    See step  8

    Result: 

    OK 

    See step  3

  3. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [09/2018 - 10/2023]

      Chassis > Brake > Clear DTCs 

    2. Turn the engine switch off.
    3. Start the engine.
    4. Perform a road test.
    5. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [09/2018 - 10/2023]

      Chassis > Brake > Trouble Codes 

      Result

      Result Proceed to
      DTCs C0500-1F and C0506-1F are not output. A
      DTCs C0500-1F and/or C0506-1F are output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2018 - 10/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 10/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023] 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [09/2018 - 10/2020]  , or refer to  REMOVAL [10/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

  4. CHECK FRONT SPEED SENSOR INSTALLATION 
    1. Turn the engine switch off.
    2. Check the speed sensor installation.

      Refer to INSTALLATION [12/2017 - 10/2023]

      GTY423344Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Speed Sensor
      *a Correct
      *b Incorrect
      *c No clearance

      OK

      There is no clearance between the sensor and the front axle hub sub-assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FRONT AXLE HUB SUB-ASSEMBLY. Refer to  REMOVAL [12/2017 - ] 

    Result: 

    OK 

    See step  5

  5. INSPECT FRONT SKID CONTROL SENSOR WIRE 
    GTY817524Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *A For RH
    *B For LH
    *1 Front Skid Control Sensor Wire
    *a Front view of wire harness connector
    (to Vehicle Side Connector)
    *b Front view of wire harness connector
    (to Sensor Side Connector)
    1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    2. Disconnect the z21, A16, A25 and/or AA3 front skid control sensor wire connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR RH

      Tester Connection Condition Specified Condition
      z21 -1 (FR+) - A25 -5 (FR+) Always Below 1 Ω
      z21 -1 (FR+) or A25 -5 (FR+) - Body ground and other terminals Always 10 MΩ or higher
      z21 -2 (FR-) - A25 -1 (FR-) Always Below 1 Ω
      z21 -2 (FR-) or A25 -1 (FR-) - Body ground and other terminals Always 10 MΩ or higher
      FOR LH

      Tester Connection Condition Specified Condition
      A16 -2 (FL+) - AA3 -3 Always Below 1 Ω
      A16 -2 (FL+) or AA3 -3 - Body ground and other terminals Always 10 MΩ or higher
      A16 -1 (FL-) - AA3 -1 Always Below 1 Ω
      A16 -1 (FL-) or AA3 -1 - Body ground and other terminals Always 10 MΩ or higher
      NOTE:

      Check the speed sensor signal after replacement.

      Refer to TEST MODE PROCEDURE [09/2018 - 10/2023]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FRONT SKID CONTROL SENSOR WIRE. Refer to  REMOVAL [12/2017 - ] 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - FRONT SKID CONTROL SENSOR WIRE) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    2. Disconnect the A9 skid control ECU (brake actuator assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR RH

      Tester Connection Condition Specified Condition
      A9-31 (FR+) - A25-5 (FR+) Always Below 1 Ω
      A9-31 (FR+) or A25-5 (FR+) - Body ground Always 10 kΩ or higher
      A9-30 (FR-) - A25-1 (FR-) Always Below 1 Ω
      A9-30 (FR-) or A25-1 (FR-) - Body ground Always 10 kΩ or higher
      FOR LH

      Tester Connection Condition Specified Condition
      A9-18 (FL+) - AA3 -3 Always Below 1 Ω
      A9-18 (FL+) or AA3 -3 - Body ground Always 10 kΩ or higher
      A9-17 (FL-) - AA3 -1 Always Below 1 Ω
      A9-17 (FL-) or AA3 -1 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. INSPECT BRAKE ACTUATOR ASSEMBLY (SENSOR INPUT) 
    1. Reconnect the A9 skid control ECU (brake actuator assembly) connector.
    2. Reconnect the AA3 or A25 front skid control sensor wire connector (for vehicle side connector).
    3. Turn the engine switch on (IG).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      FOR RH

      Tester Connection Switch Condition Specified Condition
      z21-1 (FR+) - Body ground Engine switch on (IG) 11 to 14 V
      FOR LH

      Tester Connection Switch Condition Specified Condition
      A16-2 (FL+) - Body ground Engine switch on (IG) 11 to 14 V

      HINT: 

      The front speed sensor rotor and front speed sensor are incorporated into the front axle hub sub-assembly.

      If the front speed sensor rotor needs to be replaced, replace the front axle hub sub-assembly with front speed sensor.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FRONT AXLE HUB SUB-ASSEMBLY. Refer to  REMOVAL [12/2017 - ] 

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [09/2018 - 10/2020]  , or refer to  REMOVAL [10/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

  8. CHECK FRONT SPEED SENSOR INSTALLATION 
    1. Turn the engine switch off.
    2. Check the speed sensor installation.

      Refer to INSTALLATION [12/2017 - 10/2023]

      GTY361900Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Normal
      *b Abnormal
      *c Clearance

      OK

      There is no clearance between the sensor and the front steering knuckle.

      The installation bolt is tightened properly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSTALL FRONT SPEED SENSOR CORRECTLY. Refer to  INSTALLATION [12/2017 - 10/2023] 

    Result: 

    OK 

    See step  9

  9. CHECK FRONT SPEED SENSOR AND SENSOR ROTOR 
    1. Remove the front speed sensor and the component with the sensor rotor.

      For speed sensor: Refer to REMOVAL [12/2017 - ]

      For sensor rotor: Refer to REMOVAL [12/2017 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]

    2. Check the speed sensor tip and speed sensor rotor.

      OK

      No scratches, oil, or foreign matter on the sensor tip and rotor.

      NOTE:
      • If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.

        If there are any ferrous metal filings stuck to the rotor, this will result in a malfunction, so confirm that the rotor is not contaminated with foreign matter before replacing the sensor.

      • Check the speed sensor signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [09/2018 - 10/2023]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CLEAN OR REPLACE FRONT SPEED SENSOR OR COMPONENT WITH SENSOR ROTOR 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - FRONT SPEED SENSOR) 
    1. Install the front speed sensor and the component with the sensor rotor.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    3. Disconnect the A9 Skid control ECU (brake actuator assembly) connector.
    4. Disconnect the A72 or A73 front speed sensor connector.
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR RH

      Tester Connection Condition Specified Condition
      A9-31 (FR+) - A73-5 (FR+) Always Below 1 Ω
      A9-31 (FR+) or A73-5 (FR+) - Body ground Always 10 MΩ or higher
      A9-30 (FR-) - A73-1 (FR-) Always Below 1 Ω
      A9-30 (FR-) or A73-1 (FR-) - Body ground Always 10 MΩ or higher
      FOR LH

      Tester Connection Condition Specified Condition
      A9-18 (FL+) - A72-3 (FL+) Always Below 1 Ω
      A9-18 (FL+) or A72-3 (FL+) - Body ground Always 10 MΩ or higher
      A9-17 (FL-) - A72-1 (FL-) Always Below 1 Ω
      A9-17 (FL-) or A72-1 (FL-) - Body ground Always 10 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. INSPECT BRAKE ACTUATOR ASSEMBLY (SENSOR INPUT) 
    1. Reconnect 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

      FOR RH

      Tester Connection Condition Specified Condition
      A73-5 (FR+) - Body ground Engine switch on (IG) 11 to 14 V
      FOR LH

      Tester Connection Condition Specified Condition
      A72-3 (FL+) - Body ground Engine switch on (IG) 11 to 14 V
      NOTE:

      Check the speed sensor signal after replacement.

      Refer to TEST MODE PROCEDURE [09/2018 - 10/2023]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FRONT SPEED SENSOR. Refer to  REMOVAL [12/2017 - ] 

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [09/2018 - 10/2020]  , or refer to  REMOVAL [10/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

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