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Home >> Lexus >> 2019 >> LS 500 Base, AWD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (W/ Vacuum Brake Booster) - Diagnostic Codes (3 Of 4) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster) >> DTC C1403: Rear Speed Sensor RH Malfunction; DTC C1404: Rear Speed Sensor LH Malfunction [12/2017 - 09/2018] >> Procedure

DTC C1403: Rear Speed Sensor RH Malfunction; DTC C1404: Rear Speed Sensor LH Malfunction [12/2017 - 09/2018]: Procedure

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

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

      OK

      There is no clearance between the sensor and rear axle carrier.

      The installation bolt is tightened properly.

      GTY361898Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Normal
      *b Abnormal
      *c Clearance

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  2

  2. CHECK REAR SPEED SENSOR (CHECK FOR FOREIGN MATTER) 
    1. Remove the rear speed sensor.

      Refer to REMOVAL [12/2017 - ]

    2. Check the rear speed sensor tip.

      OK

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

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

        Refer to TEST MODE PROCEDURE [12/2017 - 09/2018]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CLEAN OR REPLACE REAR SPEED SENSOR 

    Result: 

    OK 

    See step  3

  3. READ VALUE USING TECHSTREAM (REAR SPEED SENSOR) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Select the Data List using the Techstream.

      Refer to DATA LIST / ACTIVE TEST [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      RR Wheel Speed Rear wheel speed sensor RH reading Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations
      RL Wheel Speed Rear wheel speed sensor LH reading Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations

      Chassis > ABS/VSC/TRAC > Data List 

      Tester Display
      RR Wheel Speed
      RL Wheel Speed
    4. 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]

      OK

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

      NOTE:

      Check the speed sensor signal after replacement.

      Refer to TEST MODE PROCEDURE [12/2017 - 09/2018]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018] 

    Result: 

    NG 

    See step  4

  4. INSPECT SKID CONTROL SENSOR WIRE 
    1. Install the rear speed sensor and the component with the speed sensor rotor.
      GTY819776Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *A for RH
      *B for LH
      *1 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)
    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.
    3. Disconnect the z24, L178, L175 and/or LL4 skid control sensor wire connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR RH

      Tester Connection Condition Specified Condition
      z24 -2 (RR+) - L175 -3 (RR+) Always Below 1 Ω
      z24 -2 (RR+) - L175 -4 (RR-) Always 10 MΩ or higher
      z24 -2 (RR+) or L175 -3 (RR+) - Body ground Always 10 MΩ or higher
      z24 -1 (RR-) - L175 -4 (RR-) Always Below 1 Ω
      z24 -1 (RR-) - L175 -3 (RR+) Always 10 MΩ or higher
      z24 -1 (RR-) or L175 -4 (RR-) - Body ground Always 10 MΩ or higher
      FOR LH

      Tester Connection Condition Specified Condition
      L178 -2 (RL+) - LL4 -3 Always Below 1 Ω
      L178 -2 (RL+) - LL4 -4 Always 10 MΩ or higher
      L178 -2 (RL+) or LL4 -3 - Body ground Always 10 MΩ or higher
      L178 -1 (RL-) - LL4 -4 Always Below 1 Ω
      L178 -1 (RL-) - LL4 -3 Always 10 MΩ or higher
      L178 -1 (RL-) or LL4 -4 - Body ground Always 10 MΩ or higher
      NOTE:

      Check the speed sensor signal after replacement.

      Refer to TEST MODE PROCEDURE [12/2017 - 09/2018]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - 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
      A9-16 (RR+) - L175-3 (RR+) Always Below 1 Ω
      A9-16 (RR+) or L175-3 (RR+) - Body ground Always 10 kΩ or higher
      A9-15 (RR-) - L175-4 (RR-) Always Below 1 Ω
      A9-15 (RR-) or L175-4 (RR-) - Body ground Always 10 kΩ or higher
      FOR LH

      Tester Connection Condition Specified Condition
      A9-29 (RL+) - LL4 -3 Always Below 1 Ω
      A9-29 (RL+) or LL4 -3 - Body ground Always 10 kΩ or higher
      A9-28 (RL-) - LL4 -4 Always Below 1 Ω
      A9-28 (RL-) or LL4 -4 - 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 REAR SPEED SENSOR ROTOR (CHECK FOR FOREIGN MATTER) 
    1. Remove the component with the speed sensor rotor.

      Refer to REMOVAL [12/2017 - 10/2022]

    2. Check the speed sensor rotor.

      OK

      The rotor is free of scratches, oil, and foreign matter.

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

        Refer to TEST MODE PROCEDURE [12/2017 - 09/2018]

      HINT: 

      • The rear speed sensor rotor is incorporated into the rear axle hub and bearing assembly.
      • If the rear speed sensor rotor needs to be replaced, replace it together with the rear axle hub and bearing assembly.

      Result

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

    Result: 

    A 

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

    Result: 

    B 

    REPLACE REAR AXLE HUB AND BEARING ASSEMBLY. Refer to  REMOVAL [12/2017 - 10/2022] 

    Result: 

    C 

    CLEAN REAR SPEED SENSOR ROTOR 

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