Code No.U1073: Bus off


caution
  • If diagnosis code U1073 is set in the engine-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



PROBABLE CAUSES



  • Damaged wiring harness or connector
  • Malfunction of the engine-A/T-ECU

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 54D - 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.U1073 set?
Replace the engine-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 reset.
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.U1073 set?
Go to Step 1.
The procedure is complete.