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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, 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 .)
  • 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 , , , and .)

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?
Replace the steering wheel sensor.(Refer to .) Then go to Step 2.
Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting .) After repairing the CAN bus line, go to Step 3.

STEP 2. Check whether the DTC is reset.

Q. Is DTC U0428 set?
Replace the hydraulic unit (incorporates in ASC-ECU).(Refer to .) Then go to Step 3.
The procedure is complete.

STEP 3. Check whether the DTC is reset.

Q. Is DTC U0428 set?
Return to Step 1.
The procedure is complete.