INSPECTION PROCEDURE 1: Central door locking system does not work at all.


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

OPERATION


The ETACS-ECU controls the central door locking system, locking or unlocking all the doors by activating the door lock relay or the door unlock relay (built in the ETACS-ECU). The ETACS-ECU uses input signals from the front door lock actuator (driver’s side).

COMMENTS ON TROUBLE SYMPTOM


If the central door locking system does not work at all, a malfunction of the front door lock actuator (driver’s side) or ETACS-ECU is suspected.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III diagnosis code


Check that ETACS-ECU sets a diagnosis code.

Q. Is the diagnosis code set?

Refer to GROUP 54A - Diagnosis Code Chart .

Go to Step 2.

STEP 2. M.U.T.-III data list


Check the ETACS-ECU service items related to the central door locking system operation.

Item No.
 Item name
 Normal condition
20
 Driver’s door unlock switch
 ON → OFF
21
 Driver’s door lock switch
 OFF → ON

Item No.
 Item name
 Normal condition
20
 Driver’s door unlock switch
 OFF → ON
21
 Driver’s door lock switch
 ON → OFF
OK: Normal conditions are displayed for all the items.

Q. Is the check result normal?

Go to Step 3.

Refer to GROUP 54A - Inspection Procedure 4 "The front door lock actuator (driver’s side) signal is not received. ".

STEP 3. Check of short to power supply, short to earth, and open circuit in ETACS +B line and D/LOCK line between ETACS-ECU connector and fusible link.


Q. Is the check result normal?

YES : Go to Step 4.

Repair the wiring harness.

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.

Replace ETACS-ECU.