Principles of Operation (How Does it Work?)

Power Door Locks
The central security module controls the power door lock and keyless entry system. The lock and unlock operation is carried out by supplying ground to the central security module from the door lock control switch. The normal path of the actuators is to ground through the central security module. The door lock control switch will lock and unlock all doors by grounding the appropriate circuit to the central security module. The central security module then supplies power to the appropriate common actuator circuit to lock or unlock all doors. The liftgate glass release switch will only operate when all the doors are unlocked. The liftgate glass release will not operate if the vehicle speed is greater than 5 km/h (3 mph), the doors are locked, the battery has been disconnected and then reconnected, or if the module has been disconnected and then reconnected causing the liftgate glass release switch to enter disable mode. The liftgate release switch is reset by unlocking all the doors.

The door lock control switch inhibit feature will disable the door lock control switches when all doors are closed and the doors have been locked for at least 20 seconds.

Keyless Entry
Keyless entry can be achieved through either the keyless entry keypad or keyless entry remote transmitter. The keyless entry keypad is wired directly to the central security module. Pressing a keyless entry keypad button supplies a ground signal to the central security module. When the correct code is received, the central security module will unlock the driver door. If the 3/4 is pressed within five seconds of the code entry, the central security module will unlock all doors. Pressing the 7/8 and 9/0 buttons when the driver door is closed will cause the central security module to lock the doors even without the code entry. The all door lock and all door unlock functions are the same circuit and operation as pressing a door lock control switch to lock or unlock.

The keyless entry remote transmitter sends a frequency that is received by the central security module internal antenna. Depending on the frequency received, the central security module will lock all doors or unlock the driver door. If the unlock frequency is received again within three seconds of the first unlock, the central security module will unlock all doors. This function is the same as that for the keyless entry keypad.

If the frequency received is for the panic button, the central security module will cycle ground to the park lamp relay coil and horn relay coil. The park lamps and horn will continue to cycle until the panic button is pressed again, the ignition switch is turned to the RUN position, or until 2 minutes and 45 seconds has elapsed.

Autolocks
The autolock function will automatically lock the doors when the correct conditions exist. The conditions monitored for autolock are door ajar state, brake pedal and vehicle speed. The central security module monitors these inputs and when all are correct the central security module will lock all doors. For autolock to function the central security module must see a door ajar go from ajar to closed. Then the central security module will monitor the brake switch circuit for the voltage to drop indicating the brake pedal is released. The central security module will then monitor vehicle speed. When vehicle speed reaches more than 5 km/h (3 mph), the central security module will lock all doors. The vehicle will auto-relock if the door becomes ajar again and then the procedure is repeated. The autolock function can be disabled if the customer desires. Refer to Description and Operation for the correct procedure.