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, and initialize the steering angle correction amount stored in AWC-ECU.
^ 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

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. 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.

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.

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.
^ 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. Then go to Step 11.

STEP 7. Check of steering wheel sensor installation status.
Check that the steering wheel sensor is installed correctly.

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, and initialize AWC-ECU steering angle correction amount. Then go to Step 9.
NO: After adjusting the wheel alignment, calibrate the steering wheel sensor, and initialize AWC-ECU steering angle correction amount. Then go to Step 9.

STEP 9. Scan tool data list
Item 11: Steering wheel sensor.

Q: Is the check result normal?
YES: Go to Step 10.
NO: Replace the steering wheel sensor. Then go to Step 10.

STEP 10. Check whether the DTC is reset.

Q: Is DTC No. C123C set?
YES: Replace the AWC-ECU. Then go to Step 11.
NO: Intermittent malfunction. (Refer to How to Cope with Intermittent Malfunction).

STEP 11. Check whether the DTC is reset.

Q: Is DTC No. C123C set?
YES: Return to Step 1.
NO: This diagnosis is complete.