Ford 2002 Explorer Owner's Manual page 134

Controls and features
1. Insert the first previously
3
programmed coded key into the
ignition and turn the ignition from 2
2
(ACC) to 3 (ON) (maintain ignition
in 3 (ON) for at least one second).
4
2. Turn ignition to 1 (LOCK) and
remove the first coded key from
the ignition.
1
3. Within ten seconds of turning the
ignition to 2 (ACC), insert the
second previously programmed coded key into the ignition and turn the
ignition from 2 (ACC) to 3 (ON) (maintain ignition in 3 (ON) for at least
one second but no more than ten seconds).
4. Turn the ignition to 1 (LOCK) and remove the second coded key
from the ignition.
5. Within 20 seconds of turning the ignition to 2 (ACC), insert the new
unprogrammed key (new key/valet key) into the ignition and turn the
ignition from 2 (ACC) to 3 (ON) (maintain ignition in 3 (ON) for at least
one second). This step will program your new key to a coded key.
6. To program additional new unprogrammed key(s), repeat this
procedure from step 1.
If successful, the new coded key(s) will start the vehicle's engine and the
theft indicator will illuminate for three seconds and then go out.
If not successful, the new coded key(s) will not start the vehicle's engine
and the theft indicator will flash on and off and you may repeat steps 1
through 6. If failure repeats, bring your vehicle to your dealership to
have the new spare key(s) programmed.
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