ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1237/37

DTC Code DTC Name
C1237/37 Speed Sensor Rotor is Wrong Number of Teeth on One of the 4 Wheels

DESCRIPTION

This DTC is set when there is a tire size abnormality or when foreign matter is attached to the speed sensor tip or the sensor rotor.

The skid control ECU determines whether foreign matter is present, through the pulse signals transmitted by the sensor.

This DTC may be set due to defects in the connector terminal or wire harness of the speed sensor circuit.

DTC No. DTC Detecting Conditions Trouble Areas
C1237/37

When any of following (1 to 3) detected:

1. Discrepancy among four wheel speed sensor output.

2. Abnormal pulse signals from 3 or more sensors.

3. Continuous ABS control for 60 seconds or more.

  • Speed sensor rotor (Front)

  • Front Axle hub bearing

  • Speed sensor

  • Speed sensor circuit

  • Tire & wheel size

Tech Tips

C1237/37: The skid control ECU begins to detect this DTC when the vehicle speed exceeds 100 km/h (62 mph).

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT TIRES


    1. Check the tire sizes and conditions of each wheel.

      OK
      All 4 wheels are the same size and in the same condition.

    NG

    REPLACE TIRES SO THAT ALL 4 TIRES ARE SAME SIZE

    OK

  2. CHECK SPEED SENSOR ROTOR


    1. Remove the front drive shaft.

    2. A01363CE01

      Check the sensor rotor.

      OK
      No scratches or foreign matter on the sensor rotor.

    NG

    CLEAN FRONT SPEED SENSOR ROTOR OR REPLACE FRONT AXLE HUB BEARING

    OK

  3. CHECK SPEED SENSOR


    1. Remove the front speed sensor and the rear speed sensor.

    2. Check the sensor tips.

      OK
      No scratches or foreign matter on the sensor tip.

    NG

    REPLACE FRONT SPEED SENSOR OR REAR SPEED SENSOR

    OK

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


    1. Inspect the skid control ECU connector fitting for any defects.

    2. Disconnect the skid control ECU connector and the speed sensor connector.

    3. Inspect both the connector case and the terminal for deformation and corrosion.

      OK
      No deformation or corrosion.
    4. A01383QE01

      Measure the resistance.

      Standard Resistance
      Tester Connection Specified Condition
      A21-16 (FL+) - A13- 1 (FL+) Below 1 Ω
      A21-5 (FL-) - A13-2 (FL-) Below 1 Ω
      A21-9 (FR+) - A7-1 (FR+) Below 1 Ω
      A21-10 (FR-) - A7-2 (FR-) Below 1 Ω
      A21-6 (RL+) - H4-1 (RL+) Below 1 Ω
      A21-8 (RL-) - H4-2 (RL-) Below 1 Ω
      A21-17 (RR+) - H3-1 (RR+) Below 1 Ω
      A21-19 (RR-) - H3-2 (RR-) Below 1 Ω
      Standard Resistance
      Tester Connection Specified Condition
      A13-1 (FL+) - Body ground 10 kΩ or higher
      A13-2(FL-) - Body ground 10 kΩ or higher
      A7-1 (FR+) - Body ground 10 kΩ or higher
      A7-2(FR-) - Body ground 10 kΩ or higher
      H4-1 (RL+) - Body ground 10 kΩ or higher
      H4-2 (RL-) - Body ground 10 kΩ or higher
      H3-1 (RL+) - Body ground 10 kΩ or higher
      H3-2 (RL-) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE BRAKE ACTUATOR