ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1273, C1274, C1403, C1404

DTC Code DTC Name
C1273 Low Output Signal of Rear Speed Sensor RH (Test Mode DTC)
C1274 Low Output Signal of Rear Speed Sensor LH (Test Mode DTC)
C1403 Rear Speed Sensor RH Malfunction
C1404 Rear 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 (brake actuator assembly) are connected, the following waveform is output.

A01QQIMC01
*A for 4WD/AWD *B for 2WD
*1 Speed Sensor *2 Speed Sensor Rotor
*a

Waveform (Reference):

Between Speed Sensor (-) and Body Ground

 *b Low speed
*c High speed - -
DTC No. Detection Item DTC Detection Condition Trouble Area
C1273 Low Output Signal of Rear Speed Sensor RH (Test Mode DTC) Detected only during Test Mode.

  • Rear speed sensor RH (for 4WD/AWD)

  • Rear speed sensor RH (Rear axle hub and bearing assembly RH) (for 2WD)

  • Rear speed sensor rotor RH (Rear axle hub and bearing assembly RH)
C1274 Low Output Signal of Rear Speed Sensor LH (Test Mode DTC) Detected only during Test Mode.

  • Rear speed sensor LH (for 4WD/AWD)

  • Rear speed sensor LH (Rear axle hub and bearing assembly LH) (for 2WD)

  • Rear speed sensor rotor LH (Rear axle hub and bearing assembly LH)
C1403 Rear Speed Sensor RH Malfunction

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 (for 2WD) or for 30 seconds or more (for 4WD/AWD).

  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 less than 10 km/h (6 mph), outputs from both speed sensors are 0 km/h (0 mph) for 15 seconds or more (for 2WD) or for 30 seconds or more (for 4WD/AWD). (except both rear speed sensors are 0 km/h)

  • Rear speed sensor LH (for 4WD/AWD)

  • Rear speed sensor LH (Rear axle hub and bearing assembly LH) (for 2WD)

  • Rear speed sensor rotor LH (Rear axle hub and bearing assembly LH)
C1404 Rear Speed Sensor LH Malfunction

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 (for 2WD) or for 30 seconds or more (for 4WD/AWD).

  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 less than 10 km/h (6 mph), outputs from both speed sensors are 0 km/h (0 mph) for 15 seconds or more (for 2WD) or for 30 seconds or more (for 4WD/AWD). (except both rear speed sensors are 0 km/h)

  • Rear speed sensor LH (for 4WD/AWD)

  • Rear speed sensor LH (Rear axle hub and bearing assembly LH) (for 2WD)

  • Rear speed sensor rotor LH (Rear axle hub and bearing assembly LH)

Tech Tips


  • DTC C1403 and C1273 are for the rear speed sensor RH.

  • DTC C1404 and C1274 are for the rear speed sensor LH.

WIRING DIAGRAM

A01QP7TE03
A01QS0ME23
for 4WD/AWD
*a Rear Speed Sensor LH
*b Rear Speed Sensor RH
*c Skid Control ECU (Brake Actuator Assembly)

CAUTION / NOTICE / HINT

Note

Disassembly of the speed sensor from the rear axle hub and bearing assembly is prohibited (for 2WD).

PROCEDURE


  1. CHECK REAR SPEED SENSOR INSTALLATION


    1. Turn the ignition switch off.

    2. A01QQ68C01
      *a Normal
      *b Abnormal
      *c Clearance

      for 2WD:

      Check the speed sensor installation.

      OK
      There is no clearance between the sensor and the rear axle hub.

      Tech Tips

      Because the rear axle hub and bearing assembly cannot be disassembled, if the rear speed sensor needs replacement, replace the rear axle hub and bearing assembly.

    3. A01QQEAC14
      *a Normal
      *b Abnormal
      *c Clearance

      for 4WD/AWD:

      Check the rear speed sensor installation.

      Click here

      OK
      There is no clearance between the sensor and the rear axle carrier.
      The installation bolt is tightened properly.
      Result
      Proceed to
      OK (for 2WD)
      OK (for 4WD/AWD)
      NG (for 2WD)
      NG (for 4WD/AWD)

    OK (for 2WD)

    GO TO STEP 4 Click here

    NG (for 2WD)

    REPLACE REAR AXLE HUB AND BEARING ASSEMBLY Click here

    NG (for 4WD/AWD)

    INSTALL REAR SPEED SENSOR CORRECTLY Click here

    OK (for 4WD/AWD)

  2. INSPECT REAR SPEED SENSOR TIP


    1. Remove the rear 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

      Result
      Proceed to
      OK
      NG

    NG

    CLEAN OR REPLACE REAR SPEED SENSOR

    OK

  3. INSPECT REAR SPEED SENSOR ROTOR


    1. Remove the rear axle hub and bearing 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


      • 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.

    3. Reinstall the rear speed sensor and rear axle hub and bearing assembly.

      Click here for the rear speed sensor

      Click here for the rear axle hub and bearing assembly

      Result
      Proceed to
      OK
      NG

    NG

    CLEAN OR REPLACE REAR SPEED SENSOR ROTOR

    OK

  4. READ VALUE USING GTS (REAR 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.


      Chassis > ABS/VSC/TRC > 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.: 326.4 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 RH reading Min.: 0 km/h (0 mph), Max.: 326.4 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) When driving at constant speed: No large fluctuations

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      RR Wheel Speed
      RL Wheel Speed

    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).

      Note

      Check the speed sensor signal after replacement.

      Click here

      Tech Tips


      • for 2WD:

        The rear speed sensor and rear speed sensor rotor are 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 with rear speed sensor.

      • 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
      Proceed to
      OK
      NG (for 2WD)
      NG (for 4WD/AWD)

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG (for 2WD)

    REPLACE REAR AXLE HUB AND BEARING ASSEMBLY Click here

    NG (for 4WD/AWD)

  5. REPLACE REAR SPEED SENSOR


    1. Turn the ignition switch off.

    2. Replace the rear speed sensor.

      Click here

      Note

      Check the speed sensor signal after replacement.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  6. RECONFIRM DTC


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    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


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Proceed to
      DTCs C1403 and C1404 are not output
      DTCs C1403 and/or C1404 are output

      Note

      Check the speed sensor signal after replacement.

      Click here

      Tech Tips


      • 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.

      • 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


    DTCs C1403 and C1404 are not output

    END

    DTCs C1403 and/or C1404 are output

    REPLACE REAR AXLE HUB AND BEARING ASSEMBLY Click here