Ford 2003 Mustang Owner's Manual page 111

AUTOMATIC TRANSAXLE OPERATION
Brake-shift interlock
This vehicle is equipped with a brake-shift interlock
feature that prevents the gearshift from being moved
from P (Park) unless the brake pedal is depressed.
If you cannot move the gearshift out of P (Park)
with the brake pedal depressed:
1. Apply the parking brake, turn ignition key to
LOCK, then remove the key.
2. Insert the key and turn it to OFF. Apply the brake
pedal and shift to N (Neutral).
3. Start the vehicle.
If it is necessary to use the above procedure to
move the gearshift, it is possible that a fuse has
blown or the vehicle's brakelamps are not operating
properly. Refer to Fuses and relays in the Roadside
emergencies chapter.
Do not drive your vehicle until you verify
that the brakelamps are working.
If your vehicle gets stuck in mud or snow it may be
rocked out by shifting from forward and reverse
gears, stopping between shifts, in a steady pattern.
Press lightly on the accelerator in each gear.
Do not rock the vehicle for more than a few
minutes. The transmission and tires may be
damaged or the engine may overheat.
Always set the parking brake fully and make
sure the gearshift is latched in P (Park).
Turn off the ignition whenever you leave your
vehicle.
Driving
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