Code No. C123C: G and yaw rate sensor abnormality (abnormality in lateral G and yaw rate output value)



caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. 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.
  • Whenever the steering wheel sensor is replaced, always calibrate the sensor. (Refer to GROUP 35C - Steering Wheel Calibration ). Then make the steering wheel sensor learn the compensation which the PHEV-ECU has stored. (Item: Initialisation, Item No. 3: Steering Angle offset reset )
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, after vehicle information from ETACS-ECU is registered (power supply mode of the electric motor switch: OFF from ON), always carry out the calibration of all sensors (steering wheel sensor, G and yaw rate sensor, and brake fluid pressure sensor) at one time. (Refer to GROUP 35C - All Sensor Calibration ).

TROUBLE JUDGEMENT


The PHEV-ECU stores diagnosis code No. C123C when the G and yaw rate sensor fails.

PROBABLE CAUSES



  • Malfunction of G and yaw rate sensor
  • Malfunction of wheel speed sensor
  • Improper installation of steering wheel sensor
  • Malfunction of steering wheel sensor
  • Improper installation of hydraulic unit
  • Malfunction of PHEV-ECU

DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnostics


Use the 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 - Troubleshooting ). On completion, go to Step 2.

STEP 2. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Go to Step 3.
The procedure is complete.

STEP 3. M.U.T.-III other system diagnosis code



  • Use M.U.T.-III to check whether the ASC-ECU related diagnosis code is stored or not. (Refer to GROUP 35C - Diagnosis Code Chart and ).

Q. Is the diagnosis code stored?

Troubleshoot for the relevant diagnosis code.
Go to Step 4.

STEP 4. 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 stored or not (Refer to ).

Q. Is the diagnosis code stored?

Troubleshoot for the relevant diagnosis code.
Go to Step 5.

STEP 5. Check of hydraulic unit (integrated with G and yaw rate sensor) installation status.


Check that the hydraulic unit (integrated with G and yaw rate sensor) is installed correctly (Refer to GROUP 35C - Hydraulic unit (integrated with G and yaw rate sensor) ).

Q. Is the check result normal?

Go to Step 6.
Install the hydraulic unit properly, and execute "G and yaw rate sensor calibration". (Refer to Refer to GROUP 35C - G and yaw rate sensor calibration ). Then go to Step 8.

STEP 6. M.U.T.-III data list


Check that the following data list display contents are normal. (Refer to ).

  • Item No.330: Yaw rate
  • Item No.331: Lateral acceleration

Q. Is the check result normal?

Go to Step 7.
Replace the hydraulic unit (Refer to GROUP 35C - Hydraulic unit (integrated with G and yaw rate sensor) ), and execute "G and yaw rate sensor calibration". (Refer to Refer to GROUP 35C - G and yaw rate sensor calibration ). Then go to Step 11.

STEP 7. Steering wheel sensor installation check


Check that the steering wheel sensor is installed correctly (Refer to GROUP 35C - Steering Wheel Sensor ).

Q. Is the check result normal?

Go to Step 8.
Reinstall the steering wheel sensor correctly, and then go to Step 8.

STEP 8. 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 Refer to GROUP 35C - Steering Wheel Calibration ). Then go to Step 9.
After adjusting the wheel alignment, carry out calibration of steering wheel sensor to make ASC-ECU relearn the neutral point (Refer to Refer to GROUP 35C - Steering Wheel Calibration ). Then go to Step 9.

STEP 9. M.U.T.-III data list


Use M.U.T.-III to check whether the PHEV-ECU related data list is set or not. (Refer to .)

  • Item No.333: Steering angle

Q. Is the check result normal?

Go to Step 10.
Replace the steering wheel sensor (Refer to GROUP 35C - Steering Wheel Sensor ), and then go to Step 11.

STEP 10. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Replace the PHEV-ECU (Refer to ). Then go to Step 11.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

STEP 11. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Return to Step 1.
The procedure is complete.