Ford Grand Marquis Owner's Manual page 113

Programming Your Own Entry Code
You can program a personal code to unlock
your vehicle. This code does not replace the
permanent code that the dealership gave you.
Use your personal code in the same manner as
you would your original code.
To program your own code:
1. Select five digits for your personal code.
2. Enter the permanent code that the dealership
gave you.
3. Within five seconds, press 1/2.
4. Within five seconds of pressing 1/2, enter
your personal code, pressing each digit
within five seconds of the previous digit.
5. Five seconds after you press the fifth digit,
your door lock system will lock and unlock
the vehicle doors to confirm successful
programming.
The keyless entry system registers this
second code. To open your vehicle, you can
now use either code. The module remembers
only one personal code at a time. Entering a
second personal code will erase the first,
replacing it with the new second one.
To erase your personal code:
1. Enter the original permanent code.
2. Press and release 1/2 within five seconds of
Step 1.
3. Press the 1/2 button a second time and hold
for two seconds.
The keyless entry system automatically
erases your personal code. The system will
now only respond to the permanent code.
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