VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1273, C1274, C1277, C1278

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)
C1277 Abnormal Change in Output Signal of Rear Speed Sensor RH (Test Mode DTC)
C1278 Abnormal Change in Output Signal of Rear Speed Sensor LH (Test Mode DTC)

DESCRIPTION

DTCs C1273 to C1278 will be cleared when the speed sensor sends a vehicle speed signal or when Test Mode ends. DTCs from C1273 to C1278 are output only in Test Mode.

DTC Code DTC Detection Condition Trouble Area

C1273

C1274

 Detected only during Test Mode.

  • Rear speed sensor

  • Sensor installation

  • Speed sensor rotor

C1277

C1278

 Detected only during Test Mode. Speed sensor rotor

Tech Tips


  • DTCs C1273 and C1277 are for the rear speed sensor RH.

  • DTCs C1274 and C1278 are for the rear speed sensor LH.

WIRING DIAGRAM

Refer to DTCs C1403 and C1404 Click here.

INSPECTION PROCEDURE

Note

When replacing the brake actuator assembly, perform zero point calibration and store system information Click here.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)


    1. Using the GTS, check for any momentary interruption in the wire harness and connector corresponding to the DTC Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      RR Speed Open Rear speed sensor RH open detection / Error or Normal Normal -
      RL Speed Open Rear speed sensor LH open detection / Error or Normal Normal -
      Result
      Result Proceed to
      There are momentary interruptions A
      There are no momentary interruptions B
      There is a constant open circuit C

      Tech Tips

      Perform the above inspection before removing the sensor and connector.


    B

    Click here

    C

    Click here

    A

  2. REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - REAR SPEED SENSOR)


    1. Turn the engine switch off.

    2. Repair or replace the harness or connector.

    3. Check for any momentary interruption between the skid control ECU (brake actuator assembly) and the rear speed sensor Click here.

    4. Check that there are no momentary interruptions.


    NEXT

  3. PERFORM TEST MODE (SIGNAL CHECK)


    1. Turn the engine switch off.

    2. Perform the sensor check in the Test Mode procedure Click here.

      OK
      All Test Mode DTCs are cleared.

    NG

    Click here

    OK

    END

  4. READ VALUE USING GTS (RR/RL WHEEL SPEED)


    1. Turn the engine switch off.

    2. Connect the GTS to the DLC3.

    3. Start the engine.

    4. Turn the GTS on.

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

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      RR Wheel Speed Rear speed sensor RH/ min.: 0 km/h (0 mph), max.: 326 km/h (202 mph) Actual wheel speed No large fluctuations when driving at a constant speed.
      RL Wheel Speed Rear speed sensor LH/ 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 GTS.

      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 similar to the speed indicated on the speedometer.

      Tech Tips

      If troubleshooting has been carried out according to the problem symptoms table, refer back to the table and proceed to the next suspected area Click here.


    NG

    Click here

    OK

  5. PERFORM TEST MODE (SIGNAL CHECK)


    1. Turn the engine switch off.

    2. Perform the sensor check in the Test Mode procedure Click here.

      OK
      All Test Mode DTCs are cleared.

    NG

    Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  6. CHECK REAR SPEED SENSOR INSTALLATION


    1. A01FDV1E08
      Text in Illustration
      *a No clearance
      *b OK
      *c NG

      Check the speed sensor installation.

      OK
      There is no clearance between the sensor and the rear axle carrier.
      The installation bolt is tightened properly.

    NG

    INSTALL REAR SPEED SENSOR CORRECTLY Click here

    OK

  7. CHECK 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.

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


    NG

    CLEAN OR REPLACE REAR SPEED SENSOR

    OK

  8. CHECK REAR SPEED SENSOR ROTOR


    1. Remove the rear axle hub (rear speed sensor rotor) 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.


    NG

    CLEAN OR REPLACE REAR SPEED SENSOR ROTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - REAR SPEED SENSOR)


    1. Turn the engine switch off.

    2. Make sure that there is no looseness in the locking part and connecting part of the connectors.

    3. Disconnect the A13 skid control ECU (brake actuator assembly) connector.

    4. Disconnect the U32 and/or T30 rear speed sensor connector.

    5. Check the connector case and terminals for deformation and corrosion.

      Standard condition
      No deformation or corrosion.

    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for RH
      Tester Connection Condition Specified Condition
      A13-17 (RR+) - T30-1 (RR+) Always Below 1 Ω
      A13-17 (RR+) - Body ground Always 10 kΩ or higher
      A13-16 (RR-) - T30-2 (RR-) Always Below 1 Ω
      A13-16 (RR-) - Body ground Always 10 kΩ or higher
      for LH
      Tester Connection Condition Specified Condition
      A13-5 (RL+) - U32-1 (RL+) Always Below 1 Ω
      A13-5 (RL+) - Body ground Always 10 kΩ or higher
      A13-4 (RL-) - U32-2 (RL-) Always Below 1 Ω
      A13-4 (RL-) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. INSPECT SKID CONTROL ECU (SENSOR INPUT)


    1. A01FH6HE01
      Text in Illustration
      *A for RH
      *B for LH
      *a

      Front view of wire harness connector

      (to Rear Speed Sensor)

      Reconnect the skid control ECU (brake actuator assembly) connector.

    2. Disconnect the rear speed sensor connector.

    3. Check the connector case and terminals for deformation and corrosion.

      Standard condition
      No deformation or corrosion.

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      for RH
      Tester Connection Switch Condition Specified Condition
      T30-1 (RR+) - Body ground Engine switch on (IG) 8 to 14 V
      for LH
      Tester Connection Switch Condition Specified Condition
      U32-1 (RL+) - Body ground Engine switch on (IG) 8 to 14 V

      Note

      Check the speed sensor signal after replacement Click here.


    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  11. PERFORM TEST MODE (SIGNAL CHECK)


    1. Turn the engine switch off.

    2. Reconnect the rear speed sensor connector.

    3. Perform the sensor check in the Test Mode procedure Click here.

      OK
      All Test Mode DTCs are cleared.

    NG

    REPLACE REAR SPEED SENSOR Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  12. REPLACE REAR SPEED SENSOR


    1. Turn the engine switch off.

    2. Replace the rear speed sensor Click here.


    NEXT

  13. PERFORM TEST MODE (SIGNAL CHECK)


    1. Perform the sensor check in the Test Mode procedure Click here.

      OK
      All Test Mode DTCs are cleared.

    NG

    REPLACE REAR SPEED SENSOR ROTOR Click here

    OK

    END

  14. REPLACE REAR SPEED SENSOR ROTOR


    1. Turn the engine switch off.

    2. Replace the rear axle hub and bearing assembly (rear speed sensor rotor) 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.


    NEXT

  15. PERFORM TEST MODE (SIGNAL CHECK)


    1. Perform the sensor check in the Test Mode procedure Click here.

      OK
      All Test Mode DTCs are cleared.

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

    END