Code No. U1073: Bus Off


caution If diagnosis code U1073 is output from engine-A/T-ECU 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 buss 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-A/T-ECU.

PROBABLE CAUSE



  • Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

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 54D - Diagnosis - Can Bus Diagnosis Table ), and then go to Step 3 .

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

  • Reconfirm whether the diagnosis codes are output from engine-A/T-ECU.

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

Q. Are the diagnosis codes set?
Replace the engine-A/T-ECU. 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 codes are output from engine-A/T-ECU.

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

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