Code No. C123A: Abnormality in sensor calibration


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 steering wheel sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).
  • 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 stores the calibrated value of the G and yaw rate sensor, steering wheel sensor, and brake fluid pressure sensor.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the calibrated value for each sensor stored in ASC-ECU is not within the predetermined range.

  • Abnormality in neutral position of the G and yaw rate sensor
  • Abnormality in neutral position of the steering wheel sensor
  • Abnormality in neutral position of the brake fluid pressure sensor

PROBABLE CAUSES

  • Improper installation of G and yaw rate sensor or steering wheel sensor
  • ASC-ECU malfunction
  • External noise interference

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
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 Diagnosis table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is diagnosis code No.C123A set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check other diagnosis code is set.
Check if the diagnosis code related to the G and yaw rate sensor and the steering wheel sensor is set.

Q. Is any diagnosis code set?
Go to Step 4.
Perform the diagnosis for the relevant diagnosis code (Refer to .)

STEP 4. G and yaw rate sensor calibration
Perform calibration of G and yaw rate sensor (Refer to .)

Q. Has the calibration succeeded?
Go to Step 5.
Replace the hydraulic unit (ASC-ECU) (Refer to ), and then go to Step 8.

STEP 5. Steering wheel sensor calibration
Perform calibration of steering wheel sensor and calibration of steering angle sensor of ASC-ECU (Refer to ).

Q. Has the calibration succeeded?
Go to Step 6.
Replace the hydraulic unit (ASC-ECU) (Refer to ), and then go to Step 8.

STEP 6. Brake fluid pressure sensor calibration
Perform calibration of brake fluid pressure sensor (Refer to ).

Q. Has the calibration succeeded?
Go to Step 7.
Replace the hydraulic unit (ASC-ECU) (Refer to ), and then go to Step 8.

STEP 7. Check whether the diagnosis code is reset.

Q. Is diagnosis code No.C123A set?
Replace the hydraulic unit (ASC-ECU) (Refer to ), and then go to Step 8.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 8. Check whether the diagnosis code is reset.

Q. Is diagnosis code No.C123A set?
Return to Step 1.
This diagnosis is complete.