Code No.U0001: Bus off




caution
  • If diagnosis code U0001 is set in the A/T-ECU, always diagnose the CAN main bus line.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.

DIAGNOSIS CODE SET CONDITIONS


When A/T-ECU ceases communication (bus-off), code No.U0001 is set.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


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


Using M.U.T.-III, perform CAN bus line diagnosis.

Q. Is the check result normal?

Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ). Then go to Step 3.

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


Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Check if the diagnosis code is set.

Q. Is code No.U0001 set?

Replace the A/T-ECU. Then go to Step 3.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 3. Check whether the diagnosis code is set again.


Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Check if the diagnosis code is set.

Q. Is code No.U0001 set?

Go to Step 1.
The procedure is complete.