Inspection Procedure 1

INSPECTION PROCEDURE A-1: Central Door Locking System does not Work at All.

CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.










CIRCUIT OPERATION

- The ETACS-ECU controls the central door lock system, locking or unlocking all the doors by activating the central door lock relay (built into the ETACS-ECU). The ETACS-ECU uses inputs from the following components:
- Door lock actuators

- Door lock key cylinder switch

- Door lock switch, which is incorporated in the power window main switch or front power window sub switch

TROUBLESHOOTING HINTS

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

- The ETACS-ECU may be defective

DIAGNOSTIC PROCEDURE

Required Special Tools:

- MB991223: Harness Set

- MB992006: Extra Fine Probe

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)

- MB991827: M.U.T.-III USB Cable

- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check data list.

Check the input signals from the front door lock actuators.





(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. Reading and Clearing Diagnostic Trouble Codes."
(2)Turn the ignition switch to the "ON" position.
(3)Check the ETACS data list.

- Set the driver's door to "UNLOCK."





- Set the front passenger's door to "UNLOCK." [Vehicles with KOS]





(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Are normal conditions displayed on the "Dr door unlock switch" and "As door unlock switch"?

YES Go to Step 2.

NO Inspection Procedure 4.

STEP 2. Check ETACS-ECU connector C-309 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is ETACS-ECU connector C-309 in good condition?

YES Go to Step 3.
NO Repair or replace the damaged component(s). Harness Connector Inspection. Verify that the central door locking system works normally.
STEP 3. Check the wiring harness between ETACS-ECU connector C-309
(terminal 2) and fusible link (37).

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

Q. Is the wiring harness between ETACS-ECU connector C-309 (terminal 2) and fusible link
(37) in good condition?

YES Go to Step 4.
NO The wiring harness may be damaged or the connector may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
Verify that the central door locking system works normally.
STEP 4. Retest the system.

Check that the central door locking system works normally.

Q. Is the check result normal?

YES No action is necessary and testing is complete.
NO Replace the ETACS-ECU. Check that the central door locking system works normally.