Inspection Procedure A-1: 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
  • Interior lamps
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

PROBABLE CAUSES

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

DIAGNOSIS PROCEDURE

STEP 1. Connector check: D-419 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 2.
Repair the defective connector.

STEP 2. Voltage measurement at the D-419 ETACS-ECU connector.
(1)Remove the ETACS-ECU, and measure at the junction block side.
(2)Voltage between D-419 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 D-419 ETACS-ECU connector terminal No.20 and fusible link (1).
note Prior to the wiring harness inspection, check intermediate connector D-241 and junction block connector D-401, and repair if necessary.

  • Check the power supply line for open circuit and short circuit.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use troubleshooting/Inspection Service Points ).
Repair the wiring harness.

STEP 4. Resistance measurement at the D-419 ETACS-ECU connector.
(1)Remove the ETACS-ECU, and measure at the junction block side.
(2)Continuity between D-419 ETACS-ECU connector terminal No.3 and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 6.
Go to Step 5.

STEP 5. Check the wiring harness between D-419 ETACS-ECU connector terminal No.3 and body earth.
note Prior to the wiring harness inspection, check junction block connector D-405, 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 use troubleshooting/Inspection Service Points ).
Repair the wiring harness.

STEP 6. Retest the system.
Check that the following functions work normally when the ignition switch is "LOCK" (OFF) position.

  • Lamp reminder function
  • Keyless entry system
  • Ignition key cylinder illumination lamp
  • Interior lamps

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use troubleshooting/Inspection Service Points ).
Replace the ETACS-ECU.