Inspection Procedure C-4

Central Door Locking System: All the Doors do not Lock or Unlock with just the Door Lock Key Cylinder Key Operation.

Central Door Lock (Door Lock Key Cylinder Switch) Circuit:

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

TROUBLESHOOTING HINTS
- Malfunction of the power window switch (door lock switch)
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface
- 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 key cylinder 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.
2. 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."

3. Use the driver's or passenger's door lock key cylinder to lock and unlock the doors.
4. Check that scan tool MB991958 sounds.

Q: When the doors are locked and unlocked by using the driver's or front passenger's door lock key cylinder, does scan tool MB991958 sound?

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

NO: Refer to Inspection Procedure P-4 "ETACS-ECU does not receive a signal from the driver's or, front passenger's door lock key cylinder switch."