Simplified Wiring System (SWS)

DTC U1073: Bus off

CAUTION:

- If DTC U1073 is set in the ETACS-ECU, always diagnose the CAN main bus line.
- If the DTC is set as past trouble, the ECU cannot be defective. Do not replace it.

TROUBLE JUDGMENT

DTC U1073 will be stored when the ETACS-ECU ceases CAN communication error (bus off) and then resumes the communication by turning the ignition switch to the "LOCK" (OFF) position

TECHNICAL DESCRIPTION (COMMENT)

Carry out diagnosis with particular emphasis on wiring and connector(s) in the CAN bus lines. For diagnosis procedures, refer to "How to cope with past trouble" How to Treat Past Trouble).

TROUBLESHOOTING HINTS

- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.





(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958. Refer to "How to connect SWS monitor How to Connect SWS Monitor."
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the CAN bus line found to be normal?

YES Go to Step 2.

NO Repair the CAN bus line CAN Bus Diagnostics Chart).

STEP 2. Recheck for diagnostic trouble code.





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

Q. Is the DTC set?

YES Replace the ETACS-ECU. When the ETACS-ECU is replaced, register the encrypted code. Immobilizer System. After replacement, verify that the DTC is not reset.

NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).