VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1401, C1271, C1272, C1402

DTC Code DTC Name
C1401 Front Speed Sensor RH Malfunction
C1271 Low Output Signal of Front Speed Sensor RH (Test Mode DTC)
C1272 Low Output Signal of Front Speed Sensor LH (Test Mode DTC)
C1402 Front Speed Sensor LH Malfunction

DESCRIPTION

The speed sensors detect the wheel speeds and send appropriate signals to the skid control ECU (brake actuator assembly). The speed sensor has a magnet behind its detection terminal, and detects changes in magnetic flux density between the peaks and valleys of the magnetic rotor teeth.

The speed sensors detect those magnetic changes and send pulse signals to the skid control ECU (brake actuator assembly). The ECU monitors the wheel speeds through these pulse signals to control the brake control system.

Tech Tips

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

A01E2Y7E01
DTC Code DTC Detection Condition Trouble Area

C1401

C1402

One of the following conditions is met:


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

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

  • Front speed sensor RH/LH

  • Front skid control rotor RH/LH

  • Sensor installation

C1271

C1272

 Stored during Test Mode.

  • Front speed sensor RH/LH

  • Front skid control rotor RH/LH

  • Sensor installation

Tech Tips


  • DTCs C1401 and C1271 are for the front speed sensor RH.

  • DTCs C1402 and C1272 are for the front speed sensor LH.

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK FRONT SPEED SENSOR INSTALLATION


    1. Turn the ignition switch off.

    2. A01E1N8E11
      Text in Illustration
      *1 Front Speed Sensor
      *a No clearance
      *b CORRECT
      *c INCORRECT

      Check the speed sensor installation Click here.

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

    NG

    INSTALL FRONT SPEED SENSOR CORRECTLY

    OK

  2. INSPECT FRONT SPEED SENSOR TIP


    1. Turn the ignition switch off.

    2. Remove the front speed sensor Click here.

    3. Check the speed sensor tip.

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

      Note

      Do not replace the speed sensor if no damage to the speed sensor tip is found.

      Tech Tips


      • If the sensor is contaminated with oil or other foreign material, clean the sensor.

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


    NG

    CLEAN OR REPLACE FRONT SPEED SENSOR

    OK

  3. INSPECT FRONT SKID CONTROL ROTOR


    1. Turn the ignition switch off.

    2. Remove the front skid control rotor Click here.

    3. Check the front skid control rotor.

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

    NG

    CLEAN OR REPLACE FRONT SKID CONTROL ROTOR

    OK

  4. READ VALUE USING INTELLIGENT TESTER (FR/FL WHEEL SPEED)


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine.

    4. Turn the intelligent tester on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List, and then drive the vehicle.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Wheel Speed Front speed sensor RH reading / Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Actual wheel speed No large fluctuations when driving at a constant speed.
      FL Wheel Speed Front speed sensor LH reading / Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Actual wheel speed No large fluctuations when driving at a constant speed.

    6. 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, refer to the reference chart Click here.

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

    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.


    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 output Click here.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output B

    B

    REPLACE FRONT SKID CONTROL ROTOR Click here

    A

    END