42A-CENTRAL DOOR LOCKING SYSTEM DOES NOT OPERATE

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.

OPERATION

The ETACS-ECU controls the central door locking system, locking or unlocking all the doors by activating the central door lock relay (built in the ETACS-ECU). The ETACS-ECU uses input signals from the door lock switch, which is incorporated in the power window main switch.

COMMENTS ON TROUBLE SYMPTOM

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

PROBABLE CAUSES

Malfunction of the door lock switch (built in the power window main switch)
Malfunction of the front door lock actuator (driver’s side)
Malfunction of ETACS-ECU
Damaged wiring harness and connectors

DIAGNOSIS

Required Special Tools:

MB991223: Harness Set
MB992006: Extra Fine Probe

STEP 1. Using scan tool (M.U.T.-IIISE), read the diagnostic trouble code.

(1)

caution

To prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-IIISE).

Connect scan tool (M.U.T.-IIISE). Refer to GROUP 54A ETACS, "How to connect the scan tool (M.U.T.-IIISE)

(2) Turn the electric motor switch to ON.

(3) Check if an ETACS-related diagnosis trouble code is set.

(4) Turn the electric motor switch to OFF.

Is the DTC set?

Diagnose the ETACS-ECU. (Refer to GROUP 54A - ETACS, Diagnosis Trouble Code Chart

Go to Step 2

STEP 2. Using scan tool (M.U.T.-IIISE), DTC check list.

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

(1)

caution

To prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-IIISE).

Connect scan tool (M.U.T.-IIISE). Refer to GROUP 54A ETACS, "How to connect the scan tool (M.U.T.-IIISE)

(2) Turn the electric motor switch to OFF.

(3) Check the input signal related to the windshield wiper operation.

Turn the electric motor switch to ON.
Check the ETACS-ECU service items related to the central door locking system operation.

Door lock switch: Unlock → Lock.

Item No.	Item name	Normal condition
270	Dr door lock switch	Not lock → Lock

Door lock switch: Lock → Unlock.

Item No.	Item name	Normal condition
270	Dr door lock switch	Lock → Not lock

OK: Normal conditions are displayed for all the items.

Is the check result normal?

Go to Step 3

Refer to GROUP 54A - Trouble Symptom Chart for Input Signal

STEP 3. Check of short to power supply, short to ground, and open circuit in +B2 line between ETACS-ECU connector and fusible link.

Is the check result normal?

Go to Step 4

Repair the connector(s) or wiring harness.

STEP 4. Central door lock switch check.

Check that the central door lock switch is in good condition. Refer to Central Door Lock Switch Check

Is the check result normal?

Go to Step 5

Replace the power window main switch.

STEP 5. Retest the system.

Check that the central door locking system works normally.

Is the check result normal?

: No action is necessary and testing is complete.

Replace ETACS-ECU.