INSPECTION PROCEDURE A-2: When the ignition switch is at the LOCK (OFF) position, the functions do not work normally. Check the battery power supply circuit to the ETACS-ECU.


caution Whenever the ECU is replaced, ensure that the power supply circuit and the earthing circuit are normal.




COMMENTS ON TROUBLE SYMPTOM
If this circuit is defective and the ignition switch is at the LOCK (OFF) position, the ETACS-ECU does not work. In this case, the functions below will be suspended.

  • Lamp reminder function
  • Keyless entry system
  • Ignition key cylinder illumination lamp
  • Headlamp automatic-shutdown function
However, when the ignition switch is at the ON position, the functions below will work.

  • Reading diagnosis code and checking input signal by M.U.T.-III.
  • Central door locking
  • Headlamp and tail lamp
  • Hazard warning lamp
  • Interior lamps

POSSIBLE CAUSES

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

DIAGNOSTIC PROCEDURE

Step 1. Connector check: C-219 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

Step 2. Voltage measurement at the C-219 ETACS-ECU connector.


(1)Remove the ETACS-ECU, and measure at the junction block side.

(2)Voltage between C-219 ETACS-ECU connector terminal No.20 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 4.

Go to Step 3.

Step 3. Check the wiring harness between C-219 ETACS-ECU connector terminal No.20 and fusible link (26).







note Prior to the wiring harness inspection, check joint connector C-31 <RH drive vehicles>, intermediate connector C-125 and junction block connector C-203, and repair if necessary.

  • Check the power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 4. Resistance measurement at the C-219 ETACS-ECU connector.


(1)Remove the ETACS-ECU, and measure at the junction block side.

(2)Continuity between C-219 ETACS-ECU connector terminal No.3 and body earth.
OK: 2Ω or less

Q. Is the check result normal?

Go to Step 6.

Go to Step 5.

Step 5. Check the wiring harness between C-219 ETACS-ECU connector terminal No.3 and body earth.




note Prior to the wiring harness inspection, check junction block connector C-205, and repair if necessary.

  • Check the earth wires for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 6. Retest the system.
Check that the battery power supply circuit to the ETACS-ECU is normal.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.