Active Center Differential (ACD)

DTC C123C: G and Yaw Rate Sensor System (Faulty Signal)

CAUTION:

- If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.

- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

- When the steering wheel sensor is replaced, calibrate the steering wheel sensor
Testing and Inspection), and initialize the steering angle correction amount stored in AWC-ECU. (Item No.1: Steering angle correction amount initialization Actuator Test Reference Table).

- Do not drop the G and yaw rate sensor or subject it to a shock.

- When G and yaw rate sensor is replaced, calibrate G and yaw rate sensor (refer to On-vehicle Service Testing and Inspection)

OPERATION

AWC-ECU receives the G and yaw rate sensor data from ASC-ECU via the CAN communication.

DTC SET CONDITIONS

This diagnostic trouble code is set when the abnormality below is detected:

- Abnormality in G and yaw rate sensor output value

- This diagnostic trouble code is set when AWC-ECU determines that an abnormality is present by comparing the measurement values of G and yaw rate sensor with the calculation value of G and yaw rate calculated by the measurement values of the wheel speed sensor and steering wheel sensor.

PROBABLE CAUSES

- Improper installation of G and yaw rate sensor

- Malfunction of G and yaw rate sensor

- Malfunction of wheel speed sensor

- Malfunction of steering wheel sensor

- Malfunction of ASC-ECU

- Malfunction of AWC-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair the CAN bus lines. CAN Bus Diagnostics Chart).
After repairing the CAN bus line, go to Step 2.
STEP 2. Check whether the DTC is reset.

Q. Is DTC No. C123C set?

YES Go to Step 3.
NO This diagnosis is complete.
STEP 3. Scan tool diagnostic trouble code

Check the ASC diagnostic trouble code. Active Stability Control System (ASC)).

Q. Is the check result normal?

YES Perform the relevant troubleshooting.
NO Go to Step 4.
STEP 4. Scan tool diagnostic trouble code

Check if the wheel speed sensor-related, or steering wheel sensor-related diagnostic trouble code is set.

Q. Is the DTC set?

YES Perform the relevant troubleshooting.
NO Go to Step 5.
STEP 5. Check of G and yaw rate sensor installation status.

Check that the G and yaw rate sensor is installed correctly. Service and Repair).

Q. Is the check result normal?

YES Go to Step 6.
NO Reinstall the G and yaw rate sensor correctly. Then go to Step 6.
STEP 6. Scan tool data list

Check the following data list. (Refer to Data List Reference Table).

- Item No.26: Yaw rate sensor

- Item No.29: Lateral G sensor

Q. Is the check result normal?

YES Go to Step 7.
NO Replace the G and yaw rate sensor. Service and Repair). Then go to Step 11.
STEP 7. Check of steering wheel sensor installation status.

Check that the steering wheel sensor is installed correctly. Service and Repair).

Q. Is the check result normal?

YES Go to Step 8.
NO Install the steering wheel sensor correctly. Then go to Step 8.
STEP 8. Wheel alignment check.

Q. Is the check result normal?

YES After checking the wheel alignment, calibrate the steering wheel sensor Testing and Inspection), and initialize AWC-ECU steering angle correction amount (Refer to Actuator Test Reference Table). Then go to Step 9.
NO After adjusting the wheel alignment, calibrate the steering wheel sensor Testing and Inspection), and initialize AWC-ECU steering angle correction amount (Refer to Actuator Test Reference Table). Then go to Step 9.
STEP 9. Scan tool data list

Item 11: Steering wheel sensor (Refer to Data List Reference Table).

Q. Is the check result normal?

YES Go to Step 10.
NO Replace the steering wheel sensor. Service and Repair). Then go to Step 10.
STEP 10. Check whether the DTC is reset.

Q. Is DTC No. C123C set?

YES Replace the AWC-ECU. (Refer to Twin Clutch-Sportronic Shift Transmission (TC-SST)). Then go to Step 11.
NO Intermittent malfunction. How to Cope With Intermittent Malfunctions).
STEP 11. Check whether the DTC is reset.

Q. Is DTC No. C123C set?

YES Return to Step 1.
NO This diagnosis is complete.