Code No.C123B: System control too long


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.

OPERATION
ASC-ECU controls ASC by calculating the data sent from the wheel speed sensor, the steering wheel sensor, and the G and yaw rate sensor.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when ASC operates for a prolonged period.
note This diagnosis code may be set when the vehicle runs on a slippery or rough road.

PROBABLE CAUSES

  • Steering wheel sensor malfunction
  • Improper installation of steering wheel sensor
  • ASC-ECU malfunction
  • Different steering wheel
  • Wheel alignment not performed

DIAGNOSTIC PROCEDURE

STEP 1. Using M.U.T.-III, diagnose the CAN bus lines.
Using M.U.T.-III, 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 ). After repairing the CAN bus line, go to Step 2.

STEP 2. Diagnosis code recheck after repairing the CAN bus line

Q. Is diagnosis code No.C123B set?
Go to Step 3.
This diagnosis is complete.

STEP 3. M.U.T.-III diagnosis code
Check that diagnosis codes No.C100A, C1015, C1020, C102B, C1011, C101C, C1027, C1032, C1014, C101F, C102A, C1035, C1041, C1042, C1043, C1044, C1219, C2205, C123C, and C2204 are also set.

Q. Are diagnosis codes No.C100A, C1015, C1020, C102B, C1011, C101C, C1027, C1032, C1014, C101F, C102A, C1035, C1041, C1042, C1043, C1044, C1219, C2205, C123C, and C2204 also set?
Carry out the diagnosis for the diagnosis code that is set (Refer to ). Then go to Step 9.
Go to Step 4.

STEP 4. M.U.T.-III service data
Check the following data list. (Refer to ).

  • Item 08: Lateral G sensor
  • Item 09: G sensor
  • Item 12: Yaw rate sensor

Q. Is the check result normal?
Go to Step 5
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 9.

STEP 5. Check of steering wheel sensor installation status
Check that the steering wheel sensor is installed correctly.

Q. Is the check result normal?
Go to Step 6.
Install the steering wheel sensor correctly (Refer to ). Then go to Step 6.

STEP 6. Wheel alignment check
Refer to GROUP 33 - On-vehicles service/Front Wheel Alignment Check and Adjustment .

Q. Is the check result normal?
After checking the wheel alignment, perform the calibration of steering wheel sensor to make ASC-ECU relearn the neutral point (Refer to ). Then go to Step 7.
After adjusting the wheel alignment, perform the calibration of steering wheel sensor to make ASC-ECU relearn the neutral point (Refer to ). Then go to Step 7.

STEP 7. M.U.T.-III service data
Check the following data list (Refer to ).

  • Item 11: Steering angle

Q. Is the check result normal?
Go to Step 8.
Replace the steering wheel sensor (Refer to ). Then go to Step 9.

STEP 8. 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 diagnosis code No.C123B set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 9.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).

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 diagnosis code No.C123B set?
Return to Step 1.
The procedure is complete.