ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1231/31

DTC Code DTC Name
C1231/31 Steering Angle Sensor Circuit Malfunction

DESCRIPTION

The steering angle sensor signal is sent to the skid control ECU via the CAN communication system. When there is a malfunction in the CAN communication system, it will be detected by the diagnosis function.

DTC Code Information Code DTC Detection Condition Trouble Area
C1231/31 341 A steering angle sensor malfunction signal other than the sensor malfunction signal (STS1) or +B open malfunction signal (STS2), which are received as part of the steering angle sensor data, indicates the presence of a malfunction (a "stuck malfunction" is present).

  • Steering angle sensor

  • Steering angle sensor circuit

  • Steering angle sensor power supply

  • Skid control ECU
↑ 342 The sensor malfunction signal (STS1), which is received as part of the steering angle sensor data, indicates the presence of a malfunction. Steering angle sensor
↑ 344 The +B open malfunction signal (STS2), which is received as part of the steering angle sensor data, indicates the presence of a malfunction. ↑

WIRING DIAGRAM

A01GM94E02

INSPECTION PROCEDURE

Tech Tips


  • When U0073/94, U0293/59, U0123/62, U0124/95, U0126/63 or U0130/68 is output together with C1231/31, inspect and repair the trouble areas indicated by U0073/94, U0123/62, U0124/95, U0126/63 or U0130/68 first.

  • When the speed sensor or the yaw rate sensor has trouble, DTCs for the steering angle sensor may be output even when the steering angle sensor is normal. When DTCs for the speed sensor or yaw rate sensor are output together with other DTCs for the steering angle sensor, inspect and repair the speed sensor and yaw rate sensor first, and then inspect and repair the steering angle sensor.

  • Start the inspection from "CHECK HARNESS AND CONNECTOR" when using the intelligent tester and start from "CHECK DTC" when not using the intelligent tester.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)


    1. Using the intelligent tester, check for any momentary interruption in the wire harness and connectors between the skid control ECU and the steering angle sensor Click here.

      Skid control ECU:
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Steering Open Steering angle sensor open detection / Error or Normal

      Error: Momentary interruption

      Normal: Normal

      		 -
      OK
      There are no momentary interruptions.

      Tech Tips

      Perform the above inspection before removing the sensor and connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STEERING ANGLE SENSOR - SKID CONTROL ECU)

    OK

  2. CHECK DTC


    1. Clear the DTC Click here.

    2. Turn the engine switch off.

    3. Turn the engine switch on (IG) again and check that no CAN communication system DTC is output.

    4. Drive the vehicle at a speed of 35 km/h (24 mph), turn the steering wheel to the right and left, and check that no speed sensor and yaw rate sensor DTCs are output.

      Result
      Result Proceed to
      No CAN communication system DTC and speed sensor or yaw rate sensor DTC are output. A
      CAN communication system (for LHD) DTC is output. B
      CAN communication system (for RHD) DTC is output. C
      Speed sensor or yaw rate sensor DTC is output. D

      Tech Tips


      • If there is a malfunction in the speed sensor or the yaw rate sensor, an abnormal value may be output although the steering angle sensor is normal.

      • If the speed sensor and the yaw rate sensor DTCs are output simultaneously, repair the sensors and inspect the steering angle sensor.


    B

    GO TO CAN COMMUNICATION SYSTEM (for LHD) Click here

    C

    GO TO CAN COMMUNICATION SYSTEM (for RHD) Click here

    D

    CHECK FOR CIRCUIT INDICATED BY OUTPUT CODE Click here

    A

  3. CHECK TERMINAL VOLTAGE (IG, BAT)


    1. A01GKACE36

      Remove the steering wheel and the column cover lower.

    2. Disconnect the L21 sensor connector.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      L21-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      L21-3 (BAT) - Body ground Always 11 to 14 V

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

      Standard resistance
      Tester Connection Switch Condition Specified Condition
      L21-2 (ESS) - Body ground Engine switch off Below 1 Ω

      Tech Tips

      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.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG, BAT OR ESS CIRCUIT)

    OK

    REPLACE STEERING ANGLE SENSOR Click here