Code No. U1073: Bus Off


caution If diagnosis code No. U1073 is set from the BMU, diagnose the CAN bus line.
caution Before replacing the ECU, ensure that the communication circuit is normal.

TROUBLE JUDGMENT
Check Conditions
  • 5 seconds elapse after the electric motor switch is turned ON, or 5 seconds elapse after the main battery starts to be charged.
  • During the CAN communication.
Judgement Criterion
  • When the bus off of the BMU is judged.
COMMENT ON TROUBLE SYMPTOM
  • The CAN bus line harnesses and connectors may be failed, or the BMU may be failed.

FAIL-SAFE AND BACKUP FUNCTION

  • Not available

PROBABLE CAUSES

  • The harnesses and connectors are failed.
  • The BMU is failed.

DIAGNOSIS PROCEDURE


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

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

Q. Is the check result normal?
Go to Step 2 .
Repair CAN bus line (Refer to GROUP 54C - Troubleshooting - CAN Bus Diagnostics Table ). After repairing the CAN bus line, then go to Step 3 .

STEP 2. M.U.T.-III diagnosis code
Reconfirm whether the diagnosis codes are set from BMU.

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

Q. Is the diagnosis code set?
After replacing the BMU, go to Step 3 .
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 BMU.

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

Q. Is the diagnosis code set?
Go to Step 1 .
Check end.