Code No. U0001: Can Bus Off


DIAGNOSIS CODE SET CONDITIONS
  • Open circuit or short circuit occurs in the CAN communication line (CAN_H, CAN_L).
  • The communication becomes impossible with all the control modules for a specified time.

PROBABLE CAUSES



  • Malfunction of the CAN circuit
  • Malfunction of the A/T-ECU
  • Damaged harness or connector
  • Malfunction of the CAN system module

DIAGNOSIS PROCEDURE

STEP 1. Check the CAN communication system malfunction.

  • Check that the CAN system-related diagnosis code other than U0001 is set.
  • Check that the CAN-related diagnosis code is set with other relevant modules.

Q. Is the check result normal?
Go to Step 2.
Repair or replace the failure section.

STEP 2. Check the CAN communication lines.
[C-138 A/T-ECU connector (vehicle side, disconnected)]
Between C-138 terminal No. 10, 11 and the CAN communication lines of other ECU: Continuity exists.
When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness. Also, check for a short circuit between the twisted pair cables.

Q. Is the check result normal?
Go to Step 3.
Repair or replace the failure section.

STEP 3. Check the relevant ECUs and the A/T-ECU connector pin terminal, and the connection status.

Q. Is the check result normal?
Repair or replace the failure section.
Replace the A/T-ECU.