Central Locking

CENTRAL LOCKING

SYSTEM FEATURES:
- The Central Locking system controls the door locks, tailgate locks and Fuel Filler Flap actuators.
- The familiar single/double locking strategy is maintained from previous systems with a new style door lock mechanism combined with dual actuator motors similar to that of the E46 ZKE V system.
- The automatic locking feature activates the door lock actuators when a road speed signal of 7.5 MPH is detected via the K-Bus. The factory default encoding of this feature is off, but can be encoded on for individual users with the Key Memory function.
- The Driver's door lock location is the only point outside of the vehicle where the key can mechanically control the central locking system functions. The lock incorporates the familiar overrunning lock cylinder that breaks away and freewheels if an attempt is made to destroy the lock with a screwdriver, dent puller, etc.
- The selective unlocking feature is maintained. A single unlock request from the driver's door with the key or via the remote transmitter unlocks the driver's door only. A second unlock request unlocks the remaining doors and trunk. This feature can be modified for individual users with the new Key Memory capabilities to activate all lock actuators simultaneously.
- When unlocked, the X5 upper tailgate can be opened by:
- the tailgate button in the center console SZM,
- trunk release switch pad located above the license plate, or
- the trunk release button on an FZV key.
- With the upper tailgate open, the lower tailgate is then opened by depressing the switch located along it's top edge.
- GM and EWS 3.3 interface via the K bus to monitor double lock status and to initiate double lock override. This feature allows the doors to be opened from the inside if an accepted EWS key is switched on in the ignition when double locked.

DOOR LOCK ACTUATORS







The actuators are sealed, self contained units with no replaceable parts. The door lock actuators use hall effect sensors to provide:
- Door lock key position (driver's door only),
- Door open/closed status.

The driver's door lock provides the following signals to the driver's door switchblock module (PM-FT/SB):
- Lock / Unlock,
- DWA arm/disarm
- Convenience closing and opening signals.

DOOR LOCK POSITION HALL SENSORS












The Drivers door switchblock module monitors these key positions over two wires. The signals are generated by two hall effect sensors (Hall Sensor 1 & 2) located in the actuator.

When the key is turned, a plastic cylinder in the lock actuator is simultaneously rotated by the lock tumbler extension rod.

A magnet is incorporated in the plastic cylinder, which when rotated changes the magnetic influence on the hall sensors.

The presence Of a magnet in close proximity to the sensing surface of either hall sensor creates a coded input over the two wires that the GM uses to determine the key position.
- Magnet in front of sensor, current flow through the sensor is < 5 mA (0).
- Magnet rotated away from sensor, current flow through the sensor is > 12 mA (1).

Hall sensor 1 & 2 are not included in the front passenger door or rear door actuators.

DOOR CONTACT HALL SENSOR
Also included in the driver's door actuator is a third hall effect sensor. This sensor signals the door open/closed status to the driver's door switch block module and to the CM via the P-bus.







The rotary latch plate position activates the door contact hall sensor.
- When the door latch is closed, current flow through the sensor is < 5 mA (0).
- When the door is open, current flow through the sensor is > 12 mA (1).

The passenger side front door and both rear door lock actuators only include this hall effect sensor (hall sensor 3). Hall sensors 1 & 2 are not required.

ACTUATOR MOTOR CONTROL
There are two motors incorporated in each actuator that provide two separate functions:
- Single lock/unlock function. This motor controls the mechanical lock mechanism when the central lock button is pressed to single lock the vehicle. The mechanism is locked at this point but can by opened from the interior by pulling an interior door handle twice or by pressing the central lock button again. When single lock function is activated, the fuel filler flap actuator is not locked.
- Double lock/unlock function. This motor is activated only when the vehicle is locked from the outside at the driver's door lock with a key or when the GM receives a lock request from the FZV system. In this case the double lock motor is activated simultaneously with the single lock motor. The function of the double lock motor is to mechanically offset an internal rod disabling it from unlocking the vehicle from the interior. This prevents the doors from being unlocked by any means except from an unlock request at the driver's door, the FZV remote key or via central lock button.
- Continuous locking/unlocking will initiate a timed arrest of the locking system. The GM counts each time the locks are actuated. After approximately 12 cycles, the timed arrest is active. The timed arrest is deactivated one actuator cycle for every 8 seconds until the counter is reset to 0. The timed arrest is overridden if a crash signal is received from the MRS III.

All door lock actuators and the fuel filler flap actuator are controlled directly by the GM via tour internal load relays The drivers door lock actuator has a separate circuit for the selective unlocking feature

If this feature is disabled by key memory encoding, the driver's door lock actuator selective unlock circuit is activated simultaneously with the balance of the motors during unlock.

















TAILGATE CONTROL






The tailgate can be opened from the following conditions:
- Exterior tailgate switch pad above the license plate
- Interior remote tailgate button
- FZV radio key

The remote tailgate button is looked out when the GM detects a vehicle speed signal > 4 MPH via the K-bus. The switch has been incorporated into the SZM.

TAILGATE LOCK ACTUATORS
Each tailgate has a separate latching/actuator system. The upper tailgate actuator must first be activated open before the lower tailgate actuator can be operated (program logic).

When closed, the tailgate actuator position switch provides a ground signal to the GM signifying a "closed tailgate". This switch also serves as the tailgate open signal to automatically switch the interior lights on.

The lower tailgate actuator operates a lever which pulls two bowden cables to unlatch the outboard mounted latch mechanisms. The upper and lower latch mechanisms can also be manually unlatched for if electrical malfunction occurs (refer to complete vehicle section).

LOWER TAILGATE COMPONENTS







CENTRAL LOCKING BUTTON







The central lock button in the center console provides a momentary ground input signal to the GM.
- This input initiates a single lock for each door and the trunk.
- The fuel filler flap remains unlocked for refueling purposes.
- If a door is manually opened while centrally locked, the remaining doors stay locked.

The opened door can be re-locked when closed by manually locking or pushing the central button twice. This allows the locks of the remaining doors to be re-synchronized again.

As an additional safety feature, the central lock button input also unlocks a double locked system. Pressing the button returns the system to central lock (single) position, allowing the doors to be opened when the interior door handles are opened twice. This feature was also added to other ZKE systems during the 1999 model year.

CRASH SIGNALLING
The Multiple Restraint System (MRS III) provides a switched signal to the GM in the event of an accident. The signal is an output function of the MRS control module and becomes active when MRS determines a crash has occurred.

When active, the GM unlocks the door lock actuators, switches on the interior lights and signals the LCM III via the K bus to activate the hazard warning flashers.

Once the crash signal is active, the GM will not respond to lock requests from the system until the ignition switch is cycled or a front door is opened.