Power Locks: Description and Operation
HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMSThe hood latch system consists of one latch controlled by the hood release handle under the lower steering column cover.
The door latch system consists of a primary latch fastened to the inside of the door frame, controlled by the exterior and interior door handles. The door latch system has an integrated door ajar switch, door lock actuator and a driver set/reset switch (driver door only). The door locks are actuated by either a remote transmitter, the interior door lock/unlock switch (located on the driver and passenger door trim panels), manually inserting the key into the driver door lock cylinder to lock/unlock or using the keyless entry keypad.
The luggage compartment lid latch is equipped with an interior release handle and actuator. The luggage compartment lid can be locked and unlocked using the lock cylinder (valet key will not fit the lock cylinder), the luggage compartment interior trim remote switch (remote switch will open the luggage compartment lid if it is not in the lock position), the remote transmitter and keyless entry keypad.
The remote transmitter communicates with the driver door module (DDM) which controls the output functions of the driver door lock actuator. The DDM communicates through the standard corporate protocol (SCP) link to the rear electronics module (REM) and the front electronic module (FEM) for the lock and unlock commands. The REM controls the output function of the luggage compartment lid actuator and the passenger door actuators. The REM is located in the RH rear side of the luggage compartment.
The keyless entry keypad remote entry feature allows the following functions to be carried out :
- unlock the driver door (when two stage unlocking is enabled)
- unlock all doors
- lock all doors
- arm the security system
- disarm the security system
- reset a panic alarm
- recall the memory seat/mirrors/steering column/pedals position associated with a particular remote entry device (when enabled)
- release the luggage compartment lid actuator
It also lights the keypad lamp and issues illuminated entry on/off requests to the DDM when locking and unlocking. The keyless entry keypad is wired to the DDM which controls the output functions of the driver door lock. The DDM then communicates with the REM which controls the output functions of the passenger door locks and luggage compartment lid.
Individual lock cylinders are repaired by discarding the inoperative cylinder and building a new lock cylinder using the appropriate lock repair package. The lock repair package includes a detailed instruction sheet to build the new lock cylinder to the current key code of the vehicle.
PRINCIPLES OF OPERATION
Rear Electronic Module (REM)
The REM controls the output functions of the passenger door lock actuators and luggage compartment lid actuator.
Locking and Unlocking
The driver door lock function is controlled by the driver door module (DDM).
The passenger door locks and the luggage compartment lid actuator functions are controlled by the REM.
The passenger lock/unlock actuators are hard wired to the REM.
Smart Lock
The smart lock feature is controlled by the REM. This feature prevents the operator from accidentally locking the vehicle with the key in the ignition lock cylinder. The REM receives the key-in ignition status from the instrument cluster, the driver and passenger door ajar status from the FEM before this feature can function. If the key is in the ignition, the driver door ajar, and an attempt is made to lock the vehicle with the driver door lock control switch, then all doors will lock and then the driver door will unlock. If the key is in the ignition, the passenger door is ajar, and an attempt is made to lock the vehicle with the passenger door lock control switch, then all doors will lock and then all doors will unlock.
Auto Lock
The automatic door locks feature is controlled by the REM. This feature locks the doors whenever the vehicle is being driven. This feature uses inputs from the ignition switch, the digital transmission range selector, the brake pedal position (BPP) sensor and the driver and passenger door ajar switch status. The autolock function will work when the following conditions are concurrently met during the current ignition cycle:
- all doors are closed
- the autolock function is active (this function has not been disabled through the message center or any programmable options)
- ignition switch is in the RUN position
- the selected PRNDL position is any forward gear or reverse
- the vehicle speed exceeds 3 mph (5 km/h)
Autolock will be activated again if at least one door has been open and closed since the last autolock function and the following conditions are met:
- the autolock function is active (this function has not been disabled through the message center or any programmable options)
- the ignition switch is in the RUN position
- the selected PRNDL position is any forward gear or reverse
- the vehicle speed exceeds 3 mph (5 km/h)
- all doors are closed
Interior Power Lock/Unlock
The power lock/unlock function is independent of the ignition switch position. Power lock of all doors is accomplished by:
- driver or passenger door lock control switches
- lock command from the remote transmitter
- lock command from the driver set/reset switch (part of the door latch)
- keyless entry keypad
If the perimeter alarm is armed, the interior luggage compartment lid release and door lock control switches are disabled. Disarming the alarm (through valid unlock commands) will enable them.
When the LOCK button on the remote transmitter is pressed once, the power lock function will initiate the locking of all doors. If pressed twice and all doors, luggage compartment lid and hood are closed then the horn will chirp once (if horn chirp is enabled). If pressed twice and any door, luggage compartment lid or hood is open/ajar then the horn will chirp twice (if horn chirp is enabled). If two-stage unlocking is enabled, the driver door will unlock on the first occurrence of one of the following events with no other identical UNLOCK events in the past five seconds:
- a command from the remote transmitter
- a command from driver set/reset switch (part of the door latch)
- a command from keyless entry keypad
When two stage unlocking is enabled, if a subsequent unlock event of the same type occurs within five seconds without the doors being relocked, then all the doors will unlock. When two stage unlock is disabled, all doors will unlock at first (and all subsequent) unlock commands.
Luggage Compartment Lid
The luggage compartment lid feature is controlled by the FEM and the REM. The luggage compartment lid release switch is hard-wired to the FEM. When the switch is active, the FEM will send a command to the REM through the SCP communication network. The REM also needs the vehicle speed status (must be less than 5 km/h) from the network in order to activate the luggage compartment lid actuator. The REM will also activate the luggage compartment lid actuator by a command from the driver door module (DDM) through the SCP communication network (remote transmitter or keyless entry keypad.