Code No. C123C Abnormality in G and yaw rate sensor


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • Do not drop or shock the G and yaw rate sensor.
  • When the G and yaw rate sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor (Refer to , and ).

OPERATION
ABS-ECU monitors if the output of G and yaw rate sensor is normal or not.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if any malfunction below is found:

  • The output value of lateral G and yaw rate is abnormal.
  • When abnormality is detected by comparing the value output from the lateral G and yaw rate with the one from the steering wheel sensor and wheel speed sensor

PROBABLE CAUSES

  • Improper installation of the G and yaw rate sensor
  • G and yaw rate sensor malfunction
  • Steering wheel sensor malfunction
  • Improperly installed steering wheel sensor
  • Malfunction of wheel speed sensor
  • ASC-ECU malfunction
  • External noise interference

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 2.

STEP 2. M.U.T.-III diagnosis code
Check that the diagnosis code U0125 is set in ASC-ECU.

Q. Is the diagnosis code No.U0125 set?
Troubleshoot for the diagnosis code (Refer to ). Then go to Step 3.
Go to Step 3.

STEP 3. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No.C123C set?
Go to Step 4.
This diagnosis is complete.

STEP 4. Check the wheel speed sensor-related diagnosis code.
Use M.U.T.-III to check whether the wheel speed sensor-related or steering wheel sensor-related diagnosis code is set or not.

Q. Is the diagnosis code set?
Troubleshoot for the relevant diagnosis code (Refer to ).
Go to Step 5.

STEP 5. G and yaw rate sensor installation check
Check that the G and yaw rate sensor is installed correctly.

Q. Is the check result normal?
After checking the G and yaw rate sensor, carry out calibration of the G and yaw rate sensor to make ASC-ECU relearn the neutral point. (Refer to .) Then go to Step 6.
Reinstall the G and yaw rate sensor correctly (Refer to ), and then go to Step 10.

STEP 6. M.U.T.-III data list
Check the following service data (Refer to ).

  • Item 08: Lateral G-sensor
  • Item 12: Yaw rate sensor

Q. Is the check result normal?
Go to Step 7.
Replace the G and yaw rate sensor (Refer to ), and then go to Step 10.

STEP 7. Steering wheel sensor installation check
Check that the steering wheel sensor is installed correctly.

Q. Is the check result normal?
Go to Step 8.
Reinstall the steering wheel sensor correctly (Refer to ), and then go to Step 8.

STEP 8. Wheel alignment check
Refer to .

Q. Is the check result normal?
After checking the wheel alignment, carry out calibration of steering wheel sensor to make ASC-ECU relearn the neutral point. (Refer to ). Then go to Step 9.
After adjusting the wheel alignment, carry out calibration of steering wheel sensor to make ASC-ECU relearn the neutral point (Refer to ). Then go to Step 9.

STEP 9. M.U.T.-III data list
Check the following service data (Refer to ).

  • Item 11: Steering angle sensor

Q. Is the check result normal?
Go to Step 10.
Replace the steering wheel sensor (Refer to ), and then go to Step 10.

STEP 10. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No.C123C set?
Replace the hydraulic unit (ASC-ECU) (Refer to ), and then go to Step 11.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 11. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No.C123C set?
Return to Step 1.
This diagnosis is complete.