Code No. U0001 Bus-off



caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
  • If diagnosis code U0001 is set in ASC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect diagnosis code may be set. In this case, the set diagnosis code is not highly reliable.
  • Before replacing the ECU, ensure that the communication circuit is normal.
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor (Refer to , and ).

DIAGNOSIS CODE SET CONDITIONS


This diagnosis code is set when ASC-ECU has ceased the CAN communication (bus off).

COMMENTS ON TROUBLE SYMPTOM


Malfunction of wiring harness, connector (s), or ASC-ECU may be present.

PROBABLE CAUSES



  • Wiring harness or connector failure of CAN bus line
  • ASC-ECU malfunction
  • Other ECU malfunction

DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnosis


Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 3.

STEP 2. Check whether the diagnosis code is reset.


Q. Is the diagnosis code No. U0001 set?

Replace the ASC-ECU (Refer to ), and then go to Step 3.
If the trouble symptom is resolved, an intermittent malfunction such as poorly engaged connector(s) or wiring harness is suspected (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 3. Check whether the diagnosis code is reset.


Q. Is the diagnosis code No. U0001 set?

Return to Step 1.
This diagnosis is complete.