VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1237, C1275, C1276, C1277, C1278

DTC Code DTC Name
C1237 Speed Sensor Rotor Faulty
C1275 Abnormal Change in Output Signal of Front Speed Sensor RH (Test Mode DTC)
C1276 Abnormal Change in Output Signal of Front 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

The skid control ECU (brake actuator assembly) measures the speed of each wheel by receiving signals from each speed sensor.

These signals are used for recognizing that all four wheels are operating properly.

Therefore, signals from all wheels must be equal.

DTCs C1275 to C1278 are cleared when the speed sensor sends a vehicle speed signal or when Test Mode ends. DTCs C1275 to C1278 are output only in Test Mode.

DTC No. DTC Detection Condition Trouble Area
C1237

Any of the following is detected:


  1. Discrepancy among four wheel speed sensor output.

  2. Abnormal pulse signals from 3 or more sensors.

  3. Continuous ABS control is performed for 60 seconds or more.

  4. VSC control is performed for 5 seconds or more.

  • Tire and wheel size

  • Tire deformation

  • Speed sensor rotor

  • Speed sensor

  • Speed sensor circuit

  • Skid control ECU (brake actuator assembly)
C1275 Detected only during Test Mode. Front speed sensor rotor RH (front axle hub sub-assembly RH)
C1276 Detected only during Test Mode. Front speed sensor rotor LH (front axle hub sub-assembly LH)
C1277 Detected only during Test Mode. Rear speed sensor rotor RH (rear axle hub and bearing assembly RH)
C1278 Detected only during Test Mode. Rear speed sensor rotor LH (rear axle hub and bearing assembly LH)

WIRING DIAGRAM

Refer to DTCs C1330, C1331, C1332, C1333, C1464, C1465, C1466 and C1467 (See page for front, and Click here for rear).

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration Click here.

Tech Tips

When C1330, C1331, C1332, C1333, C1464, C1465, C1466 and/or C1467 is output together with C1237, inspect and repair the trouble areas indicated by C1330, C1331, C1332, C1333, C1464, C1465, C1466 and/or C1467 first (See page for C1330, C1331, C1464 and C1465, and Click here for C1332, C1333, C1466 and C1467).

PROCEDURE


  1. CHECK TIRES


    1. Check the size and condition of all four tires Click here.

      Tech Tips

      The DTC is output when tire deformation or a difference in tire size is detected.

      OK
      The diameter of all four tires and the tire pressure are the same.

    NG

    REPLACE TIRES SO THAT ALL FOUR TIRES ARE THE SAME SIZE

    OK

  2. READ VALUE USING GTS (SPEED SENSOR)


    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Select the Data List on the GTS Click here.

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

    4. 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 pressure, 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.
      Result
      Result Proceed to
      OK A
      NG (for front) B
      NG (for rear) C

    B

    CHECK FRONT SPEED SENSOR AND SENSOR ROTOR Click here

    C

    INSPECT SKID CONTROL SENSOR WIRE Click here

    A

  3. PERFORM TEST MODE INSPECTION (SIGNAL CHECK)


    1. Turn the ignition switch off.

    2. Perform the sensor check using Test Mode Procedure Click here.

      OK
      All Test Mode DTCs are not output.
      Result
      Result Proceed to
      OK A
      NG (for front) B
      NG (for rear) C

    B

    CHECK FRONT SPEED SENSOR AND SENSOR ROTOR Click here

    C

    INSPECT SKID CONTROL SENSOR WIRE Click here

    A

  4. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch off.

    4. Start the engine.

    5. Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.

    6. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1237 is not output. A
      DTC C1237 is output (for front). B
      DTC C1237 is output (for rear). C

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE FRONT SPEED SENSOR Click here

    C

    REPLACE REAR AXLE HUB AND BEARING ASSEMBLY Click here

  5. CHECK FRONT SPEED SENSOR AND SENSOR ROTOR


    1. Remove the front speed sensor and the component with the sensor rotor (See page for speed sensor, Click here for sensor rotor).

    2. Check the speed sensor tip and speed sensor rotor.

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

      Note


      • If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.

        If there are any ferrous metal filings stuck to the rotor, this will result in a malfunction, so confirm that the rotor is not contaminated with foreign matter before replacing the sensor.

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


    NG

    CLEAN OR REPLACE FRONT SPEED SENSOR OR COMPONENT WITH SENSOR ROTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - FRONT SPEED SENSOR)


    1. Install the front speed sensor and the component with the sensor rotor.

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

    3. Disconnect the A84 skid control ECU (brake actuator assembly) connector and A23 or A24 front speed sensor connector.

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

      Standard Resistance
      for RH
      Tester Connection Condition Specified Condition
      A84-18 (FR+) - A23-1 (FR+) Always Below 1 Ω
      A84-18 (FR+) or A23-1 (FR+) - Body ground Always 10 kΩ or higher
      A84-29 (FR-) - A23-2 (FR-) Always Below 1 Ω
      A84-29 (FR-) or A23-2 (FR-) - Body ground Always 10 kΩ or higher
      for LH
      Tester Connection Condition Specified Condition
      A84-21 (FL+) - A24-1 (FL+) Always Below 1 Ω
      A84-21 (FL+) or A24-1 (FL+) - Body ground Always 10 kΩ or higher
      A84-33 (FL-) - A24-2 (FL-) Always Below 1 Ω
      A84-33 (FL-) or A24-2 (FL-) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. RECONFIRM DTC


    1. Reconnect the A84 skid control ECU (brake actuator assembly) connector and A23 or A24 front speed sensor connector.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch off.

    4. Start the engine.

    5. Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.

    6. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1237 is output. A
      DTC C1237 is not output. B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  8. 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

  9. 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 54 km/h (34 mph) or more for at least 120 seconds.

    5. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1237 is output. A
      DTC C1237 is not output. B

    B

    END

    A

  10. REPLACE FRONT AXLE HUB SUB-ASSEMBLY


    1. Turn the ignition switch off.

    2. Replace the front speed sensor rotor (front axle hub sub-assembly) Click here.

      Tech Tips

      The front speed sensor rotor is incorporated into the front axle hub sub-assembly.

      If the front speed sensor rotor needs to be replaced, replace the front axle hub sub-assembly.

      Note

      Check the speed sensor signal after replacement Click here.


    NEXT

  11. 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 54 km/h (34 mph) or more for at least 120 seconds.

    5. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1237 is output. A
      DTC C1237 is not output. B

    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    END

  12. INSPECT SKID CONTROL SENSOR WIRE


    1. A004TN3E02
      Text in Illustration
      *A for RH
      *B for LH
      *a Front view of skid control sensor wire
      *b

      Front view of wire harness connector

      (to Sensor Side Connector)
      *c

      Front view of wire harness connector

      (to Vehicle Side Connector)

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

    2. for RH:

      Disconnect the z2 and zH2 rear skid control sensor wire connectors.

    3. for LH:

      Disconnect the z1 and zG3 skid control sensor wire connectors.

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

      Standard Resistance
      for RH
      Tester Connection Condition Specified Condition
      z2-2 (RR+) - zH2-1 Always Below 1 Ω
      z2-2 (RR+) - zH2-2 Always 10 kΩ or higher
      z2-2 (RR+) or zH2-1 - Body ground Always 10 kΩ or higher
      z2-1 (RR-) - zH2-2 Always Below 1 Ω
      z2-1 (RR-) - zH2-1 Always 10 kΩ or higher
      z2-1 (RR-) or zH2-2 - Body ground Always 10 kΩ or higher
      for LH
      Tester Connection Condition Specified Condition
      z1-2 (RL+) - zG3-1 Always Below 1 Ω
      z1-2 (RL+) - zG3-2 Always 10 kΩ or higher
      z1-2 (RL+) or zG3-1 - Body ground Always 10 kΩ or higher
      z1-1 (RL-) - zG3-2 Always Below 1 Ω
      z1-1 (RL-) - zG3-1 Always 10 kΩ or higher
      z1-1 (RL-) or zG3-2 - Body ground Always 10 kΩ or higher

      Note

      Check the speed sensor signal after replacement Click here.


    NG

    REPLACE SKID CONTROL SENSOR WIRE Click here

    OK

  13. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE)


    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    2. Disconnect the A84 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      for RH
      Tester Connection Condition Specified Condition
      A84-19 (RR+) - zH2-1 Always Below 1 Ω
      A84-19 (RR+) or zH2-1 - Body ground Always 10 kΩ or higher
      A84-5 (RR-) - zH2-2 Always Below 1 Ω
      A84-5 (RR-) or zH2-2 - Body ground Always 10 kΩ or higher
      for LH
      Tester Connection Condition Specified Condition
      A84-7 (RL+) - zG3-1 Always Below 1 Ω
      A84-7 (RL+) or zG3-1 - Body ground Always 10 kΩ or higher
      A84-20 (RL-) - zG3-2 Always Below 1 Ω
      A84-20 (RL-) or zG3-2 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  14. RECONFIRM DTC


    1. for RH:

      Reconnect the z2 and zH2 rear skid control sensor wire connectors.

    2. for LH:

      Reconnect the z1 and zG3 skid control sensor wire connectors.

    3. Reconnect the A84 skid control ECU (brake actuator assembly) connector.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off.

    6. Start the engine.

    7. Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.

    8. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1237 is output. A
      DTC C1237 is not output. B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  15. REPLACE REAR AXLE HUB AND BEARING ASSEMBLY


    1. Turn the ignition switch off.

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

      Note

      Check the speed sensor signal after replacement Click here.


    NEXT

  16. 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 54 km/h (34 mph) or more for at least 120 seconds.

    5. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1237 is output. A
      DTC C1237 is not output. B

    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    END