Inspection Procedure C-3

Central Door Locking System: All the Doors do not Lock or Unlock with just 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: Test Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface (V.C.I.)
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B

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 the special tool. Refer to "How to connect SWS monitor." How to Connect SWS Monitor
2. When the driver's or the front passenger's door lock switch is moved from "LOCK" to "UNLOCK" and vice versa, check if scan tool MB991958 sounds or not.
3. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "Pulse Checking."

Q: Does scan tool MB991958 sound when the driver's or the front passenger's door lock switch is moved from "LOCK" to "UNLOCK" and vice versa?

YES: Replace the ETACS-ECU. All the doors should be locked and unlocked by the door lock switch.

NO: Refer to Inspection Procedure P-6 "ETACS-ECU does not receive a signal from the door lock switch (incorporated in the power window main switch)."