Erasing Personal Code; Unlocking The Doors And Releasing The Trunk With The Keyless Entry System - Mercury Grand Marquis 2002 Owner's Manual

All of the vehicle doors will lock and unlock to confirm programming of
the new code.
Do not set a code that includes five of the same number or presents
them in sequential order. Thieves can easily figure out these types of
codes.
You can program up to three personal codes to unlock your vehicle.
These codes do not replace the permanent code that the dealership gave
you.

Erasing personal code

To erase all of the personal entry codes programmed to a vehicle:
1. Enter the factory-set code.
2. Press and release 1/2 within 5
seconds of step 1.
3. Press and hold 1/2 for two
seconds. All of the vehicle doors will
lock and then unlock to confirm
erasure.
Unlocking the doors and releasing the trunk with the keyless entry
system
To unlock the driver door, enter either the factory-set code or personal
code (each digit pressed within 5 seconds of prior digit). The interior
lamps will illuminate.
To unlock all doors, enter the
factory-set code or personal code
(driver door unlocks) and press 3/4
within five seconds.
Locks and Security
3 4
1 2 5 6
1 2 3 4 5 6
7 8 9 0
7 8 9 0
101