Inspection Procedure C-4

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 key cylinder switch or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Trouble in input signal system
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The ETACS-ECU may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-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 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 the special tool. Refer to "How to connect SWS monitor."
2. When the doors are locked and unlocked by using the driver's or passenger's door lock key cylinder, check that scan tool MB991958 sounds.
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: When the doors are locked and unlocked by using the driver's or passenger's door lock key cylinder, does scan tool MB991958 sound?

YES: Replace the ETACS-ECU. When the ETACS-ECU is replaced,register the encrypted code. Refer to Encrypted Code Registration Criteria Table in Antitheft and Alarm Systems. Check that all the doors should be locked and unlocked by using each door lock key cylinder switch.

NO: Refer to Inspection Procedure N-3 "ETACS-ECU does not receive any signal from the door lock key cylinder switch."