Code No. U1073: Bus Off


caution If diagnosis code U1073 is output from engine-ECU <M/T> or engine-A/T-ECU <A/T> surely perform CAN busline diagnosis.
caution Replace ECU after certainly confirming that the communication circuits are normal.

TROUBLE JUDGMENT


Check Condition
  • All the time
Judgment Criterion
  • When the bus off error is detected.
COMMENT ON TROUBLE SYMPTOM
  • The failure is possibly caused by malfunction of the harness and connector in CAN busline or by malfunction in engine-ECU <M/T> or engine-A/T-ECU <A/T>.

PROBABLE CAUSES



  • Failed harness and connector
  • Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS

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 54D - Troubleshooting - CAN Bus Diagnostics Table ), and then go to Step 3 .

STEP 2. M.U.T.-III diagnosis code
Reconfirm whether the diagnosis code is output from engine-ECU <M/T> or engine-A/T-ECU <A/T>.

  1. Erase the diagnosis code being output.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis code is output.

Q. Are the diagnosis codes output?
Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>. Then 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 code is output from engine-ECU <M/T> or engine-A/T-ECU <A/T>.

  1. Erase the diagnosis code being output.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis code is output.

Q. Are the diagnosis codes output?
Go to Step 1 .
Check end.