Code No. C123C Sensor cluster malfunction


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 - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the steering wheel sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).

OPERATION
ASC-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

  • 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 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No.C123C set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check the other 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 4.

STEP 4. Check whether the ASC-ECU is installed properly.
Check whether the ASC-ECU is installed correctly. Refer to .

Q. Is the check result normal?
Execute "Lateral G sensor calibration" on "Special function". After the calibration is performed (Refer to ) , turn the ignition switch from "OFF" to "ON".Then go to Step 5.
Install the ASC-ECU properly, and execute "Lateral G sensor calibration" on "Special function". After the calibration is performed (Refer to ) , turn the ignition switch from "OFF" to "ON".Then go to Step 5.

STEP 5. M.U.T.-III data list
Check the following data list (Refer to ).

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

Q. Is the check result normal?
Go to Step 6.
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then go to Step 10.

STEP 6. Steering wheel sensor installation check
Check that the steering wheel sensor is installed correctly.

Q. Is the check result normal?
Go to Step 7.
Reinstall the steering wheel sensor correctly (Refer to ), and then go to Step 7.

STEP 7. 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 8.
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 8.

STEP 8. M.U.T.-III data list
Check the following data list (Refer to ).

  • Item 11: Steering angle sensor

Q. Is the check result normal?
Go to Step 9.
Replace the steering wheel sensor (Refer to ), and then go to Step 9.

STEP 9. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Turn the steering wheel to either right or left at 20 km/h or more.
note The ASC warning/operation lamp and the ASC OFF lamp may remain on until the vehicle speed reaches approx. 10 km/h, then the steering wheel is turned to either right or left.

Q. Is the diagnosis code No.C123C set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then go to Step 10.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).

STEP 10. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Turn the steering wheel to either right or left at 20 km/h or more.
note The ASC warning/operation lamp and the ASC OFF lamp may remain on until the vehicle speed reaches approx. 10 km/h, then the steering wheel is turned to either right or left.

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