Bus-Off

DTC U0001: Bus-off

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.
^ If diagnostic trouble code U0001 is set in ASC-ECU, always diagnose 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 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.

DTC SET CONDITIONS
This diagnostic trouble code is set when ASC-ECU has ceased CAN communication (bus off).

PROBABLE CAUSES
^ Wiring harness or connector failure of CAN bus line
^ ASC-ECU malfunction
^ ECU malfunction of other system

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

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: Go to Step 2.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 3.

STEP 2. Check whether the DTC is reset.

Q: Is DTC U0001 set?
YES: Replace the hydraulic unit (incorporates in ASC-ECU). Then go to Step 3.
NO: Intermittent malfunction.

STEP 3. Check whether the DTC is reset.
Q: Is DTC U0001 set?
YES: Return to Step 1.
NO: The procedure is complete.