Active Stability Control System (ASC)

DTC U0428: Communication error in steering wheel sensor

CAUTION:

- If diagnostic trouble code U0428 is set in ASC-ECU, always diagnose the CAN bus lines. If there is any fault in the CAN bus lines Initial Inspection and Diagnostic Overview ), an incorrect DTC may be set.
- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
- When the steering wheel sensor is replaced, always perform calibration to make ASC-ECU learn the neutral point (Refer to Testing and Inspection ).
- When the hydraulic unit (integrated with ASC-ECU) is replaced, after turning the ignition switch ON and OFF (vehicle information from ETACS-ECU is registered), always perform the calibration of steering wheel sensor, G and yaw rate sensor, brake fluid pressure sensor, cut valve, and inlet valve (Refer to G and Yaw Rate Sensor Calibration , Testing and Inspection , Master Cylinder Brake Fluid Pressure Sensor Calibration , and Testing and Inspection ).

CIRCUIT OPERATION

The steering wheel sensor outputs the steering wheel status to ASC-ECU via the CAN bus lines.

DTC SET CONDITIONS

This diagnostic trouble code is set when ASC-ECU has detected the communication error in the steering wheel sensor.

PROBABLE CAUSES

- Steering wheel sensor malfunction
- ASC-ECU malfunction
- External noise interference

DIAGNOSIS

Required Special Tools:

- MB991958 Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827 M.U.T.-III USB Cable
- MB991910 M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

YES Replace the steering wheel sensor (Refer to Service and Repair). Then go to Step 2.
NO Repair the CAN bus lines CAN Bus Diagnostics Chart).
After repairing the CAN bus line, go to Step 3.
STEP 2. Check whether the DTC is reset.

Erase the DTC.

Q. Is DTC U0428 set?

YES Replace the hydraulic unit (integrated with ASC-ECU) (Refer to Service and Repair). Then go to Step 3.
NO The procedure is complete.
STEP 3. Check whether the DTC is reset.

Erase the DTC.

Q. Is DTC U0428 set?

YES Return to Step 1.
NO The procedure is complete.