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). Speed sensor rotors have 48 serrations The hall IC type speed sensor uses the frequency of output pulses to detect the vehicle speed.

Because the sensor outputs digital pulses, it can detect vehicle speeds even when the vehicle is nearly stationary.

A01CGOCE02
DTC No. DTC Detection Condition Trouble Area

C1403

C1404

When any of following conditions detected:


  • When one of the front wheel speeds is 0 km/h (0 mph) or more, and two of the other wheel speeds are 12 km/h (7 mph) or more, one of the wheels has no pulse signal for 30 seconds or more continuously.

  • When the vehicle starts moving, 3 of the wheels are 10 km/h or more, but only one wheel is less than 2 km/h (1 mph) for 0.4 seconds or more continuously.

  • At a vehicle speed of 20 km/h or more, the front two wheels have no pulse signal for 20 seconds or more continuously, occurring in 8 consecutive IG ON←→IG OFF cycles.

  • Harness or connector

  • Rear speed sensor RH/LH

  • Rear skid control rotor RH/LH

  • Rear speed sensor installation

  • Brake actuator assembly

C1273

C1274

 Detected only during Test Mode.

  • Harness or connector

  • Rear speed sensor RH/LH

  • Rear skid control rotor RH/LH

  • Rear speed sensor installation

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

A01CHTME02

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (REAR SPEED SENSOR)


    1. Warm up the engine.

    2. Turn the ignition switch off.

    3. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    4. Connect the intelligent tester to the DLC3.

    5. Turn the ignition switch to ON.

    6. Turn the intelligent tester on.

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

    8. According to the display on the intelligent tester, read the Data List.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      RR Wheel Speed RR 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
      RL Wheel Speed RL 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

    9. 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.

      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).

    NG

    CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - REAR SPEED SENSOR) Click here

    OK

  2. PERFORM TEST MODE INSPECTION (SIGNAL CHECK)


    1. Turn the ignition switch off.

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

      OK
      All Test Mode DTCs are cleared.
      Result
      Result Proceed to
      NG A
      OK B

    B

    CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - REAR SPEED SENSOR) Click here

    A

  3. CHECK REAR SPEED SENSOR INSTALLATION


    1. Turn the ignition switch off.

    2. A01CHFPE04
      Text in Illustration
      *1 Rear Speed Sensor
      *a No clearance
      *b OK
      *c NG

      Check the rear speed sensor installation.

      OK
      There is no clearance between the rear speed sensor and the rear steering knuckle.

    NG

    INSTALL REAR SPEED SENSOR CORRECTLY Click here

    OK

  4. INSPECT REAR SPEED SENSOR TIP


    1. Remove the rear speed sensor Click here.

    2. Check the rear speed sensor tip.

      OK
      No scratches, oil, or foreign matter on the rear speed sensor tip.

      Note

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

    3. Reinstall the rear speed sensor.


    NG

    CLEAN OR REPLACE REAR SPEED SENSOR Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - REAR SPEED SENSOR)


    1. Turn the ignition switch off.

    2. Disconnect the B9 skid control ECU (brake actuator assembly) connector.

    3. Disconnect the R12 and/or R11 rear speed sensor connector.

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

      Standard Resistance
      RH
      Tester Connection Condition Specified Condition
      B9-16 (RR+) - R12-2 (RR+) Always Below 1 Ω
      B9-17 (RR-) - R12-1 (RR-) Always Below 1 Ω
      B9-16 (RR+) or R12-2 (RR+) - Body ground Always 10 kΩ or higher
      B9-17 (RR-) or R12-1 (RR-) - Body ground Always 10 kΩ or higher
      LH
      Tester Connection Condition Specified Condition
      B9-5 (RL+) - R11-2 (RL+) Always Below 1 Ω
      B9-4 (RL-) - R11-1 (RL-) Always Below 1 Ω
      B9-5 (RL+) or R11-2 (RL+) - Body ground Always 10 kΩ or higher
      B9-4 (RL-) or R11-1 (RL-) - Body ground Always 10 kΩ or higher

    5. Reconnect the B9 skid control ECU (brake actuator assembly) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT BRAKE ACTUATOR ASSEMBLY (SENSOR INPUT)


    1. A01CH5EE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Rear Speed Sensor)
      *b RH
      *c LH

      Turn the ignition switch to ON.

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

      Standard Voltage
      RH
      Tester Connection Switch Condition Specified Condition
      R12-2 (RR+) - Body ground Ignition switch ON 8 to 17 V
      LH
      Tester Connection Switch Condition Specified Condition
      R11-2 (RL+) - Body ground Ignition switch ON 8 to 17 V

    3. Reconnect the R12 and/or R11 rear speed sensor connector.


    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  7. RECONFIRM DTC


    1. Clear the DTC 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
      DTC is not output A
      DTC is output B

    B

    REPLACE REAR SPEED SENSOR Click here

    A

    USE SIMULATION METHOD TO CHECK Click here

  8. REPLACE REAR SPEED SENSOR


    1. Replace the rear speed sensor Click here.


    NEXT

  9. RECONFIRM DTC


    1. Clear the DTC 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
      DTC is not output A
      DTC is output B

    B

    REPLACE REAR SKID CONTROL ROTOR Click here

    A

    END

  10. REPLACE REAR SKID CONTROL ROTOR


    1. Replace the rear skid control rotor Click here.


    NEXT

  11. RECONFIRM DTC


    1. Clear the DTC 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
      DTC is not output A
      DTC is output B

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    END