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DTC C123B: System Control too Long
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC 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.
 
 
 
DTC SET CONDITIONS
This DTC is set when ASC operates for a prolonged period.
noteThis DTC 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
 
 
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), check DTC
Check that wheel speed sensor, G and yaw rate sensor and steering wheel sensor related DTC are also set.
Are wheel speed sensor, G and yaw rate sensor and steering wheel sensor related DTC also set?
Carry out the diagnosis for the DTC that is set (Refer to ).
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check data list
Check the following data list. (Refer to ).
  • Item No.06: Yaw rate sensor
  • Item No.08: Lateral G sensor
  • Item No.09: G sensor
Is the check result normal?
Go to Step 3.
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
 
STEP 3. Check for column switch assembly (integrated with steering wheel sensor) installation
Refer to GROUP 54A - Column Switch .
Is the check result normal?
Go to Step 4.
Repair it.
 
STEP 4. Wheel alignment check
Refer to GROUP 33 - On-vehicle Service, Front wheel alignment check and adjustment .
Is the check result normal?
Go to Step 5.
Repair it.
 
STEP 5. Using scan tool (M.U.T.-IIISE), check data list
Check the following data list (Refer to ).
  • Item No.05: Steering angle sensor
Is the check result normal?
Go to Step 6.
Replace the column switch assembly (integrated with steering wheel sensor) (Refer to GROUP 54A - Column Switch ).
 
STEP 6. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position.
(4) Turn the steering wheel to either right or left at 20 km/h (12 mph) or more.
noteThe ASC warning/operation light and the ASC OFF light may remain on until the vehicle speed reaches approx. 10 km/h (6 mph), then the steering wheel is turned to either right or left.
Is diagnostic trouble code No.C123B set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).