VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1401, C1402

DTC Code DTC Name
C1401 Front Speed Sensor RH Malfunction
C1402 Front Speed Sensor LH Malfunction

DESCRIPTION

The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU (brake actuator assembly). These signals are used for brake control.

The speed sensor generates vehicle speed pulses based on the rotation of the skid control rotor. The skid control ECU (brake actuator assembly) detects the speed of each wheel using this vehicle speed pulse.

Tech Tips

When the connectors between the speed sensor and skid control ECU (brake actuator assembly) are connected, the following waveform is output.

A003ASDE01
Text in Illustration
*1 Front Speed Sensor *2 Front Skid Control Rotor
*a

Waveform (Reference):

Between Speed Sensor (-) and Body Ground

 *b Low speed
*c High speed - -
DTC No. DTC Detection Condition Trouble Area

C1401

C1402

Either of the following is detected:


  1. At a vehicle speed of 10 km/h (6 mph) or more, output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more.

  2. At a vehicle speed less than 10 km/h (6 mph), output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more.

  3. At a vehicle speed of 10 km/h (6 mph) or more, outputs from both front speed sensors are 0 km/h (0 mph) for 15 seconds or more. (except both rear speed sensors are 0 km/h (0 mph))

  • Front speed sensor RH/LH

  • Sensor installation

  • Front skid control rotor RH/LH

Tech Tips


  • DTC C1401 is for the front speed sensor RH.

  • DTC C1402 is for the front speed sensor LH.

WIRING DIAGRAM

A003AYYE01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK FRONT SPEED SENSOR INSTALLATION


    1. Turn the ignition switch off.

    2. A003FYBE13
      Text in Illustration
      *a Normal
      *b Abnormal
      *c Clearance

      Check the speed sensor installation Click here.

      OK
      There is no clearance between the sensor and the front steering knuckle.
      The installation bolt is tightened properly.

    NG

    INSTALL FRONT SPEED SENSOR CORRECTLY Click here

    OK

  2. INSPECT FRONT SPEED SENSOR TIP


    1. Remove the front speed sensor Click here.

    2. Check the speed sensor tip.

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

      Note


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

      • If there is iron powder sticking to the rotor, this will result in a malfunction, so confirm that the rotor is not contaminated with foreign material before replacing the sensor.

      • Check the speed sensor signal after cleaning or replacement Click here.


    NG

    CLEAN OR REPLACE FRONT SPEED SENSOR

    OK

  3. INSPECT FRONT SKID CONTROL ROTOR


    1. Remove the front skid control rotor Click here.

    2. Check the front skid control rotor.

      OK
      No scratches, oil or foreign matter on the rotor.

      Note

      Check the speed sensor signal after cleaning or replacement Click here.

    3. Reinstall the front speed sensor and the front skid control rotor Click here for speed sensor, Click here for skid control rotor).


    NG

    CLEAN OR REPLACE FRONT SKID CONTROL ROTOR

    OK

  4. READ VALUE USING GTS (FRONT SPEED SENSOR)


    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

    4. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    5. According to the display on the GTS, read the Data List.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Wheel Speed Front 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
      FL Wheel Speed Front 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

    6. Check that there is no difference between the speed value output from the speed sensor displayed on the GTS and the speed value displayed on the speedometer when driving the vehicle.

      Tech Tips

      Factors that affect the indicated vehicle speed include tire size, tire inflation, 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 Click here.

      OK
      The speed value output from the speed sensor displayed on the GTS is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.


    NG

    REPLACE FRONT SPEED SENSOR Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here

  5. REPLACE FRONT SPEED SENSOR


    1. Turn the ignition switch off.

    2. Replace the front speed sensor Click here.

      Note

      Check the speed sensor signal after replacement Click here.


    NEXT

  6. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Turn the ignition switch off.

    3. Start the engine.

    4. Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.

    5. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTCs C1401 and C1402 are not output A
      DTCs C1401 and/or C1402 are output B

      Note

      Check the speed sensor signal after replacement Click here.


    B

    REPLACE FRONT SKID CONTROL ROTOR Click here

    A

    END