Diagnosis code No.03 Communication error with front-ECU

caution

If diagnosis code No.03 is set in the ETACS-ECU, diagnose the CAN bus lines.

TROUBLE JUDGMENT

The ETACS-ECU communicates with the front-ECU through the SWS communication line. If there is any trouble in that communication, diagnosis code No.03 will be set.

COMMENTS ON TROUBLE SYMPTOM

The front-ECU, the ETACS-ECU, connector(s), or wiring harness between the two may be defective.

POSSIBLE CAUSES

Malfunction of the front ECU
Malfunction of the ETACS-ECU
Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

Step 1. M.U.T.-III CAN bus diagnostics

Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

	Go to Step 2.

	Repair the CAN bus line (Refer to GROUP 54F - Troubleshooting ).

Step 2. Check whether the diagnosis code is reset.

Check again if the diagnosis code is set.

(1)Erase the diagnosis code.

(2)Ignition switch: LOCK (OFF) position to ON

(3)On completion, check that the diagnosis code is not reset.

Q. Is the check result normal?

	If a trouble is solved, it is determined that there is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00 - How to use troubleshooting/Inspection Service Points ).

	Go to Step 3.

Step 3. ECU check by using the SWS monitor

Check that the power supply and earth lines to the ETACS-ECU and the front-ECU and the SWS communication lines are normal.

Ignition switch: OFF

ECUS TO BE CHECKED

Front ECU
ETACS-ECU

OK: "OK" are displayed for all the items

Q. Are the check result normal?

	Normal conditions are displayed for all the items. : Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

	"NG" is displayed on the "FRONT ECU" menu. : Refer to Inspection Procedure A-4 "Communication with front-ECU is impossible ."

	"NG" is displayed on the "ETACS ECU" menu. : Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible ."