Code No.U1073: Bus off


caution If diagnosis code U1073 is set in the SRS-ECU, diagnose the CAN main bus line.
caution Whenever the ECU is replaced, ensure that the communication circuit is normal.

DIAGNOSIS CODE SET CONDITIONS


diagnosis code U1073 will be stored when the SRS-ECU ceases CAN communication (bus off) and then resumes the communication when the ignition switch is turned to the "LOCK" (OFF) position.

COMMENT ON TROUBLE SYMPTOM


The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the SRS-ECU may be defective.

PROBABLE CAUSE



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
warning Since the radiator fan rotates during CAN bus line diagnostics, make sure that no one is servicing the engine compartment before diagnosing the CAN bus line. Since the CAN communication stops when diagnosing the CAN bus line, the ETACS-ECU detects the time-out of the engine-ECU, and activates the radiator fan to prevent overheating as fail-safe.
Use the M.U.T.-III to check the CAN bus lines.

Q. Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C, Troubleshooting - Can Bus Diagnosis Table ).

STEP 2. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set.

  1. Erase the diagnosis code.
  2. Turn the ignition switch to the "ON" position.
  3. Check if the diagnosis code is set.
  4. Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the diagnosis code U1073 set?
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
Replace the SRS-ECU (Refer to ).