VEHICLE STABILITY CONTROL SYSTEM(for TMC Made), Diagnostic DTC:C1271, C1272, C1401, C1402

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

DESCRIPTION

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

Speed sensor rotors have rows of alternating N and S magnetic poles, and their magnetic fields change when the rotors turn.

Each speed sensor detects that magnetic change and sends a pulse signal to the skid control ECU (brake actuator assembly).

Tech Tips

When the connectors between the speed sensor and skid control ECU are connected, the following waveform is output.

A01VHPTE03
Text in Illustration
*1 Speed Sensor *2 Speed Sensor 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

Any 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

  • Speed sensor rotor

  • Sensor installation
Test Mode Diagnosis Code
DTC No. DTC Detection Condition Trouble Area

C1271

C1272

 Detected only during Test Mode.

  • Front speed sensor RH/LH

  • Speed sensor rotor

  • Sensor installation

Tech Tips


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

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

WIRING DIAGRAM

A01VM2PE04

PROCEDURE


  1. CHECK FRONT SPEED SENSOR INSTALLATION


    1. Turn the ignition switch off.

    2. A01VKUPE05
      Text in Illustration
      *a Normal
      *b Abnormal
      *c Clearance

      Check the speed sensor 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)

    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

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

    3. Reinstall the front speed sensor Click here


    NG

    CLEAN OR REPLACE FRONT SPEED SENSOR

    OK

  3. INSPECT FRONT SPEED SENSOR ROTOR


    1. Remove the front axle hub sub-assembly Click here.

    2. Check the speed sensor rotor.

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

      Note

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

      Tech Tips

      If the front axle hub assembly needs to be replaced, replace it together with the front drive outboard joint shaft assembly.

    3. Reinstall the front axle hub assembly Click here.


    NG

    CLEAN OR REPLACE FRONT SPEED SENSOR ROTOR

    OK

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


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

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

      ABS/VSC/TRC (Skid Control ECU)
      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 km/h (202 mph) Vehicle stopped: 0 km/h When driving at constant speed: No large fluctuations
      FL Wheel Speed FL wheel speed sensor reading /min.: 0 km/h (0 mph), max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h When driving at constant speed: No large fluctuations

    5. Check that there is no difference between the speed value output from the speed sensor displayed on the intelligent tester 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 intelligent tester 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 the Problem Symptoms Table, refer back to the table and proceed to the next step Click here.

      Result
      Result Proceed to
      NG A
      OK B

    B

    CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) Click here

    A

  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. Start the engine.

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

    4. 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.

      Tech Tips


      • If the front axle hub assembly needs to be replaced, replace it together with the front drive outboard joint shaft assembly.

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


    A

    END

    B

    REPLACE FRONT SPEED SENSOR ROTOR Click here