Code No. U0001: Bus Off



caution If diagnosis code U0001 is stored in the engine-ECU, surely perform CAN busline diagnosis.
caution Replace ECU after certainly confirming that the communication circuits are normal.

TROUBLE JUDGMENT


Check Condition
Judgment Criterion

FAIL-SAFE AND BACKUP FUNCTION




COMMENT ON TROUBLE SYMPTOM




PROBABLE CAUSE




DIAGNOSIS PROCEDURE


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



  • Using M.U.T.-III, perform CAN busline diagnosis.

Q. Is the check result normal?

Go to Step 2.
Correct CAN busline (Refer to GROUP 54C - Troubleshooting - Can Bus Diagnostics Table ), and then go to Step 3.

STEP 2. M.U.T.-III diagnosis code



  • Reconfirm whether the diagnosis codes are set from engine-ECU.

  1. Erase the diagnosis codes being set.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis codes are set.

Q. Are the diagnosis codes set?

Replace the engine-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 3. M.U.T.-III diagnosis code



  • Reconfirm whether the diagnosis codes are set from engine-ECU.

  1. Erase the diagnosis codes being set.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis codes are set.

Q. Are the diagnosis codes set?

Go to Step 1.
The check is end.