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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 65 (Electronically Controlled Brake System (Diagnostic Codes) (2 Of 4) (Hybrid)) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model) >> DTC C1401: Malfunction in Front Speed Sensor RH Circuit; DTC C1402: Malfunction in Front Speed Sensor LH Circuit [07/2022 - ] >> Procedure

DTC C1401: Malfunction in Front Speed Sensor RH Circuit; DTC C1402: Malfunction in Front Speed Sensor LH Circuit [07/2022 - ]: Procedure

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  1. CHECK DTC 
    1. Clear the DTCs.

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

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the power switch off.
    3. Turn the power switch on (IG).
    4. Check if the same DTC is output.

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

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTC C1401 is output. A
      DTC C1402 is output. B

    Result: 

    B 

    See step  10

    Result: 

    A 

    See step  2

  2. CHECK FRONT SPEED SENSOR RH INSTALLATION 
    1. Check the front speed sensor RH installation.

      OK

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

      The installation bolt is tightened properly.

      Torque 

      8.5 N.m (87 kgf/cm, 75 in.lbf)

      GTY483599Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Speed Sensor RH
      *a OK
      *b NG
      *c 8.5 N.m
      *d No Clearance

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REINSTALL OR REPLACE FRONT SPEED SENSOR RH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK FRONT SPEED SENSOR RH (CHECK FOR FOREIGN MATTER) 
    1. Remove the front speed sensor RH.

      Refer to REMOVAL [07/2022 - ]

    2. Check the front speed sensor tip RH.

      OK

      The sensor tip is free of scratches, oil, and foreign matter.

      NOTE:
      • If there is oil or foreign matter on the front speed sensor RH, clean the front speed sensor RH.
      • If the front speed sensor RH is damaged, replace the front speed sensor RH with a new one.
      • Check the front speed sensor RH signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [10/2018 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CLEAN OR REPLACE FRONT SPEED SENSOR RH 

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM (FR WHEEL SPEED) 
    1. Install the front speed sensor RH.
    2. Select the Data List on the Techstream.

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

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FR Wheel Speed Front speed sensor RH Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      FR Wheel Speed
    3. Check the front speed sensor RH output value.

      OK

      The output value changes in accordance with the vehicle speed.

      Result

      Result Proceed to
      OK A
      NG (w/o AVS) B
      NG (w/ AVS) C

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - ] 

    Result: 

    C 

    See step  7

    Result: 

    B 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - FRONT SPEED SENSOR RH) 
    1. Turn the power switch off.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      OK

      The connector is securely connected.

    3. Disconnect the A37 skid control ECU (brake booster with master cylinder assembly) connector.
    4. Disconnect the A28 front speed sensor RH connector.
    5. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A37-3 (FR+) - A28-6 (FR+) Always Below 1 Ω
      A37-3 (FR+) or A28-6 (FR+) - Body ground Always 10 kΩ or higher
      A37-4 (FR-) - A28-5 (FR-) Always Below 1 Ω
      A37-4 (FR-) or A28-5 (FR-) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK FRONT SPEED SENSOR ROTOR RH (CHECK FOR FOREIGN MATTER) 
    1. Remove the front speed sensor RH and the component with the front speed sensor rotor RH.

      for Front Speed Sensor RH: Refer to REMOVAL [07/2022 - ]

      for Front Speed Sensor Rotor RH: Refer to REMOVAL [07/2022 - ]

    2. Check the front speed sensor rotor RH.

      OK

      The front speed sensor rotor RH is free of scratches, oil, and foreign matter.

      NOTE:
      • If there is oil or foreign matter on the front speed sensor rotor RH, clean the front speed sensor rotor RH.
      • If the front speed sensor rotor RH is damaged, replace the front speed sensor rotor RH with a new one.
      • Check the front speed sensor RH signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [10/2018 - ]

      HINT: 

      • The front speed sensor rotor RH is incorporated into the front axle hub sub-assembly RH.
      • If the front speed sensor rotor RH needs to be replaced, replace it together with the front axle hub sub-assembly RH.

      Result

      Result Proceed to
      OK A
      NG (The front speed sensor rotor RH is damaged.) B
      NG (There is foreign matter on the front speed sensor rotor RH.) C

    Result: 

    A 

    REPLACE FRONT SPEED SENSOR RH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    B 

    REPLACE FRONT AXLE HUB SUB-ASSEMBLY RH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    C 

    CLEAN FRONT SPEED SENSOR ROTOR RH 

  7. INSPECT SKID CONTROL SENSOR WIRE WITH SUSPENSION CONTROL RH 
    1. Turn the power switch off.
      GTY1125816Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of skid control sensor wire with suspension control RH
      *b Front view of wire harness connector
      (to Sensor Side Connector)
      *c Front view of wire harness connector
      (to Vehicle Side Connector)
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      OK

      The connector is securely connected.

    3. Disconnect the B and A79 skid control sensor wire with suspension control RH connectors.
    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
      B-1 (FR+) - A79-6 (FR+) Always Below 1 Ω
      B-1 (FR+) or A79-6 (FR+) - Body ground and other terminals Always 10 kΩ or higher
      B-2 (FR-) - A79-5 (FR-) Always Below 1 Ω
      B-2 (FR-) or A79-5 (FR-) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE SKID CONTROL SENSOR WIRE WITH SUSPENSION CONTROL RH 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - SKID CONTROL SENSOR WIRE WITH SUSPENSION CONTROL RH) 
    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 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
      A37-3 (FR+) - A79-6 (FR+) Always Below 1 Ω
      A37-3 (FR+) or A79-6 (FR+) - Body ground Always 10 kΩ or higher
      A37-4 (FR-) - A79-5 (FR-) Always Below 1 Ω
      A37-4 (FR-) or A79-5 (FR-) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK FRONT SPEED SENSOR ROTOR RH (CHECK FOR FOREIGN MATTER) 
    1. Remove the front speed sensor RH and the component with the front speed sensor rotor RH.

      for Front Speed Sensor RH: Refer to REMOVAL [07/2022 - ]

      for Front Speed Sensor Rotor RH: Refer to REMOVAL [07/2022 - ]

    2. Check the front speed sensor rotor RH.

      OK

      The front speed sensor rotor RH is free of scratches, oil, and foreign matter.

      NOTE:
      • If there is oil or foreign matter on the front speed sensor rotor RH, clean the front speed sensor rotor RH.
      • If the front speed sensor rotor RH is damaged, replace the front speed sensor rotor RH with a new one.
      • Check the front speed sensor RH signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [10/2018 - ]

      HINT: 

      • The front speed sensor rotor RH is incorporated into the front axle hub sub-assembly RH.
      • If the front speed sensor rotor RH needs to be replaced, replace it together with the front axle hub sub-assembly RH.

      Result

      Result Proceed to
      OK A
      NG (The front speed sensor rotor RH is damaged.) B
      NG (There is foreign matter on the front speed sensor rotor RH.) C

    Result: 

    A 

    REPLACE FRONT SPEED SENSOR RH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    B 

    REPLACE FRONT AXLE HUB SUB-ASSEMBLY RH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    C 

    CLEAN FRONT SPEED SENSOR ROTOR RH 

  10. CHECK FRONT SPEED SENSOR LH INSTALLATION 
    1. Check the front speed sensor LH installation.

      OK

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

      The installation bolt is tightened properly.

      Torque 

      8.5 N.m (87 kgf/cm, 75 in.lbf)

      GTY483599Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Speed Sensor LH
      *a OK
      *b NG
      *c 8.5 N.m
      *d No Clearance

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REINSTALL OR REPLACE FRONT SPEED SENSOR LH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    OK 

    See step  11

  11. CHECK FRONT SPEED SENSOR LH (CHECK FOR FOREIGN MATTER) 
    1. Remove the front speed sensor LH.

      Refer to REMOVAL [07/2022 - ]

    2. Check the front speed sensor tip LH.

      OK

      The sensor tip is free of scratches, oil, and foreign matter.

      NOTE:
      • If there is oil or foreign matter on the front speed sensor LH, clean the front speed sensor LH.
      • If the front speed sensor LH is damaged, replace the front speed sensor LH with a new one.
      • Check the front speed sensor LH signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [10/2018 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CLEAN OR REPLACE FRONT SPEED SENSOR LH 

    Result: 

    OK 

    See step  12

  12. READ VALUE USING TECHSTREAM (FL WHEEL SPEED) 
    1. Install the front speed sensor LH.
    2. Select the Data List on the Techstream.

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

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FL Wheel Speed Front speed sensor LH Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      FL Wheel Speed
    3. Check the front speed sensor LH output value.

      OK

      The output value changes in accordance with the vehicle speed.

      Result

      Result Proceed to
      OK A
      NG (w/o AVS) B
      NG (w/ AVS) C

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - ] 

    Result: 

    C 

    See step  15

    Result: 

    B 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - FRONT SPEED SENSOR LH) 
    1. Turn the power switch off.
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      OK

      The connector is securely connected.

    3. Disconnect the A37 skid control ECU (brake booster with master cylinder assembly) connector.
    4. Disconnect the A13 front speed sensor LH connector.
    5. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A37-31 (FL+) - A13-6 (FL+) Always Below 1 Ω
      A37-31 (FL+) or A13-6 (FL+) - Body ground Always 10 kΩ or higher
      A37-32 (FL-) - A13-5 (FL-) Always Below 1 Ω
      A37-32 (FL-) or A13-5 (FL-) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. CHECK FRONT SPEED SENSOR ROTOR LH (CHECK FOR FOREIGN MATTER) 
    1. Remove the front speed sensor LH and the component with the front speed sensor rotor LH.

      for Front Speed Sensor LH: Refer to REMOVAL [07/2022 - ]

      for Front Speed Sensor Rotor LH: Refer to REMOVAL [07/2022 - ]

    2. Check the front speed sensor rotor LH.

      OK

      The front speed sensor rotor LH is free of scratches, oil, and foreign matter.

      NOTE:
      • If there is oil or foreign matter on the front speed sensor rotor LH, clean the front speed sensor rotor LH.
      • If the front speed sensor rotor LH is damaged, replace the front speed sensor rotor LH with a new one.
      • Check the front speed sensor LH signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [10/2018 - ]

      HINT: 

      • The front speed sensor rotor LH is incorporated into the front axle hub sub-assembly LH.
      • If the front speed sensor rotor LH needs to be replaced, replace it together with the front axle hub sub-assembly LH.

      Result

      Result Proceed to
      OK A
      NG (The front speed sensor rotor LH is damaged.) B
      NG (There is foreign matter on the front speed sensor rotor LH.) C

    Result: 

    A 

    REPLACE FRONT SPEED SENSOR LH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    B 

    REPLACE FRONT AXLE HUB SUB-ASSEMBLY LH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    C 

    CLEAN FRONT SPEED SENSOR ROTOR LH 

  15. INSPECT SKID CONTROL SENSOR WIRE WITH SUSPENSION CONTROL LH 
    1. Turn the power switch off.
      GTY1129056Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of skid control sensor wire with suspension control LH
      *b Front view of wire harness connector
      (to Sensor Side Connector)
      *c Front view of wire harness connector
      (to Vehicle Side Connector)
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

      OK

      The connector is securely connected.

    3. Disconnect the A and A78 skid control sensor wire with suspension control LH connectors.
    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
      A-1 (FL+) - A78-6 (FL+) Always Below 1 Ω
      A-1 (FL+) or A78-6 (FL+) - Body ground and other terminals Always 10 kΩ or higher
      A-2 (FL-) - A78-5 (FL-) Always Below 1 Ω
      A-2 (FL-) or A78-5 (FL-) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE SKID CONTROL SENSOR WIRE WITH SUSPENSION CONTROL LH 

    Result: 

    OK 

    See step  16

  16. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - SKID CONTROL SENSOR WIRE WITH SUSPENSION CONTROL LH) 
    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 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
      A37-31 (FL+) - A78-6 (FL+) Always Below 1 Ω
      A37-31 (FL+) or A78-6 (FL+) - Body ground Always 10 kΩ or higher
      A37-32 (FL-) - A78-5 (FL-) Always Below 1 Ω
      A37-32 (FL-) or A78-5 (FL-) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  17

  17. CHECK FRONT SPEED SENSOR ROTOR LH (CHECK FOR FOREIGN MATTER) 
    1. Remove the front speed sensor LH and the component with the front speed sensor rotor LH.

      for Front Speed Sensor LH: Refer to REMOVAL [07/2022 - ]

      for Front Speed Sensor Rotor LH: Refer to REMOVAL [07/2022 - ]

    2. Check the front speed sensor rotor LH.

      OK

      The front speed sensor rotor LH is free of scratches, oil, and foreign matter.

      NOTE:
      • If there is oil or foreign matter on the front speed sensor rotor LH, clean the front speed sensor rotor LH.
      • If the front speed sensor rotor LH is damaged, replace the front speed sensor rotor LH with a new one.
      • Check the front speed sensor LH signal after cleaning or replacement.

        Refer to TEST MODE PROCEDURE [10/2018 - ]

      HINT: 

      • The front speed sensor rotor LH is incorporated into the front axle hub sub-assembly LH.
      • If the front speed sensor rotor LH needs to be replaced, replace it together with the front axle hub sub-assembly LH.

      Result

      Result Proceed to
      OK A
      NG (The front speed sensor rotor LH is damaged.) B
      NG (There is foreign matter on the front speed sensor rotor LH.) C

    Result: 

    A 

    REPLACE FRONT SPEED SENSOR LH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    B 

    REPLACE FRONT AXLE HUB SUB-ASSEMBLY LH. Refer to  REMOVAL [07/2022 - ] 

    Result: 

    C 

    CLEAN FRONT SPEED SENSOR ROTOR LH 

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