ELECTRONICALLY CONTROLLED BRAKE SYSTEM(w/o Vacuum Brake Booster), Diagnostic DTC:C1231

DTC Code DTC Name
C1231 Steering Angle Sensor Circuit

DESCRIPTION

The skid control ECU assembly receives steering sensor signals via CAN communication. When a communication malfunction between the skid control ECU and steering sensor occurs, DTC U0126 (Lost Communication with Steering Sensor Module) is stored.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1231 Steering Angle Sensor Circuit

341

342

344

  • INF Code: 341


    • While steering sensor communication is enabled, a malfunction signal output is received during the sensor self-check (stuck malfunction).

  • INF Code: 342


    • When sensor malfunction excluding steering sensor +B malfunction occurs.

  • INF Code: 344


    • While steering sensor communication is enabled, a malfunction signal output is received during the sensor self-diagnosis (internal malfunction).

    • When steering sensor malfunction +B occurs.

  • INF Code: 341


    • Steering sensor power supply

    • Steering sensor

    • w/ Variable Gear Ratio Steering System

      VGRS ECU (front steering control ECU)

  • INF Code: 342, 344


    • Steering sensor

 -
DTC Detection Conditions: C1231 INF Code: 344
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition Steering sensor communication data available stat ○ -
Malfunction Status A sensor malfunction signal is received (internal malfunction detected via sensor self-diagnosis) ○ -
When a steering sensor +B malfunction occurs - ○
Detection Time - -
Number of Trips 1 trip 1 trip

WIRING DIAGRAM

B006GIDE01
B006A54E01

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following procedure.

Tech Tips


  • When U0126 is output together with C1231, inspect and repair the trouble areas indicated by U0126 first.

    Click here

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

PROCEDURE


  1. CHECK DTC


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the engine switch off.

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

      Click here

    4. Drive the vehicle at a speed of 35 km/h (22 mph), turn the steering wheel to the right and left, and check that no speed sensor and/or yaw rate sensor DTCs are output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C1231 is output. A
      CAN communication system DTCs are output. B
      Speed sensor and/or yaw rate sensor DTCs are output. C
      DTC C1231 is not output. D

      Tech Tips


      • When CAN communication system DTCs are output, repair the CAN communication system before repairing each corresponding sensor.

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

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


    B

    INSPECT CAN COMMUNICATION SYSTEM Click here

    C

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    D

    USE SIMULATION METHOD TO CHECK Click here

    A

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. Turn the engine switch off.

    2. Remove the steering wheel and column cover.

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

    4. Disconnect the G30*1 or G29*2 steering sensor connector.

      *1: w/o Variable Gear Ratio Steering System

      *2: w/ Variable Gear Ratio Steering System

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

      Standard Voltage
      w/o Variable Gear Ratio Steering System
      Tester Connection Condition Specified Condition
      G30-4 (BAT) - Body ground Always 11 to 14 V
      w/ Variable Gear Ratio Steering System
      Tester Connection Condition Specified Condition
      G29-4 (BAT) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


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

      Standard Voltage
      w/o Variable Gear Ratio Steering System
      Tester Connection Switch Condition Specified Condition
      G30-9 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V
      w/ Variable Gear Ratio Steering System
      Tester Connection Switch Condition Specified Condition
      G29-9 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT) Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (GROUND TERMINAL)


    1. Turn the engine switch off.

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

      Note

      Before measuring the resistance of the steering sensor, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or switches, or opening or closing the doors.

      Standard Resistance
      w/o Variable Gear Ratio Steering System
      Tester Connection Condition Specified Condition
      G30-6 (ESS) - Body ground 1 minute after engine switch off Below 1 Ω
      w/ Variable Gear Ratio Steering System
      Tester Connection Condition Specified Condition
      G29-6 (ESS) - Body ground 1 minute after engine switch off Below 1 Ω
      Result
      Proceed to
      OK
      NG (w/o Variable Gear Ratio Steering System)
      NG (w/ Variable Gear Ratio Steering System)

    OK

    REPLACE STEERING SENSOR Click here

    NG (w/o Variable Gear Ratio Steering System)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)

    NG (w/ Variable Gear Ratio Steering System)

  5. CHECK HARNESS AND CONNECTOR (VGRS ECU (FRONT STEERING CONTROL ECU) - STEERING SENSOR)


    1. Disconnect the G79 VGRS ECU (front steering control ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G79-1 (+BO) - G29-4 (BAT) Always Below 1 Ω
      G79-1 (+BO) or G29-4 (BAT) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (VGRS ECU (FRONT STEERING CONTROL ECU))


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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G79-7 (+BI) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE VGRS ECU (FRONT STEERING CONTROL ECU) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR