Code No.C123B: Prolonged operation of ASC


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
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
  • G and yaw rate sensor malfunction
  • Improper installation of steering wheel sensor, or G and yaw rate sensor
  • ASC-ECU malfunction
  • Different steering wheel
  • Wheel alignment not performed

DIAGNOSIS 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 - Troubleshooting .) 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 10.
Go to Step 4.

STEP 4. Check of G and yaw rate sensor installation status
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, perform the calibration of the G and yaw rate sensor to make ASC-ECU relearn the neutral point. (Refer to .) Then go to Step 5.
Reinstall the G and yaw rate sensor correctly. (Refer to .) Then go to Step 10.

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

  • Item 08: Lateral G sensor
  • Item 09: G sensor <Vehicles for 4WD>
  • Item 12: Yaw rate sensor

Q. Is the check result normal?
Go to Step 6.
Replace the G and yaw rate sensor. (Refer to .) Then go to Step 10.

STEP 6. 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 7.
Install the steering wheel sensor correctly. (Refer to .) Then go to Step 7.

STEP 7. Wheel alignment check
Refer to GROUP 33 - On-vehicles service .

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 8.
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 8.

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

  • Item 11: Steering angle

Q. Is the check result normal?
Go to Step 9.
Replace the steering wheel sensor. (Refer to .) Then go to Step 10.

STEP 9. Check whether the diagnosis code is reset.
Drive the vehicle 40 km/h or more for more than 15 seconds

Q. Is diagnosis code No.C123B set?
Replace the hydraulic unit (ASC-ECU). (Refer to .) Then go to Step 10.
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

STEP 10. Check whether the diagnosis code is reset.
Drive the vehicle 40 km/h or more for more than 15 seconds

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