Inspection Procedure C-3

Central Door Locking System: All the doors do not lock or unlock with the door lock switch operation.

Central Door Lock (Door Lock Switch) Circuit:

TECHNICAL DESCRIPTION (COMMENT)
The door lock switch (built into the power window switch) or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- The power window switch (door lock switch) may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A

Check the input signal (by using the pulse check mode of the monitor).

Check the input signals from the door lock switch.

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.




1. Connect scan tool MB991958 to the data link connector (16-pin).
2. Operate the scan tool MB991958 as follows:
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "PULSE CHECK."

3. Move the driver's or the front passenger's door lock switch from "LOCK" to "UNLOCK" or vice versa.
4. Check the scan tool MB991958 sounds or not.

Q: Does scan tool MB991958 sound when operating the door lock switches as described?

YES: Replace the ETACS-ECU. Verify that all the doors can now be locked and unlocked by the door lock switch.

NO: Refer to Inspection Procedure O-7 "ETACS-ECU does not receive a signal from the door lock switch (incorporated in the power window main switch)."