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. These signals are used for the ABS control system. This speed sensor contains a sensor IC, which consists of 2 MREs (Magnetic Resistance Elements). The speed sensor rotor, which consists of 48 sets of N and S poles arranged in a circle, is integrated with the inner race of the hub bearing.

To detect the rotation direction, the output waves are used to determine the relationship of the pulses that are generated by the 2 MREs. Upon receiving this signal, the sensor IC outputs a forward or backward waveform to the ECU.

A0162H7E07
DTC Code DTC Detection Condition Trouble Area

C1401

C1402

Any of the following is detected:


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

  • Front speed sensor RH/LH

  • Speed sensor rotor

Tech Tips


  • DTC C1401 is for the front speed sensor RH.

  • DTC C1402 is for the front speed sensor LH.

WIRING DIAGRAM

A01617FE31

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK FRONT SPEED SENSOR INSTALLATION


    1. A0161GYE07

      Check the speed sensor installation.

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

    NG

    INSTALL FRONT SPEED SENSOR CORRECTLY Click here

    OK

  2. READ VALUE USING INTELLIGENT TESTER (FRONT SPEED SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Select the Data List on the intelligent tester Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Wheel Speed FR wheel speed sensor reading / min.: 0 km/h (0 mph), max.: 326.4 km/h (202 mph)

      When vehicle is stopped: 0 km/h (0 mph)

      When vehicle is being driven at a constant speed: No major fluctuation

      		 Similar speed as indicated on speedometer
      FL Wheel Speed FL wheel speed sensor reading /min.: 0 km/h (0 mph), max.: 326.4 km/h (202 mph)

      When vehicle is stopped: 0 km/h (0 mph)

      When vehicle is being driven at a constant speed: No major fluctuation

      		 Similar speed as indicated on speedometer

    4. Check the speed value output from the speed sensor displayed on the intelligent tester.

      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 intelligent tester is the similar speed as indicated on the speedometer.

      Note

      Check the speed sensor signal after replacement Click here

      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 AND FRONT SPEED SENSOR ROTOR

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here