How to Reset an Anti-Theft System for a Mercury Mountaineer

by Allen Moore
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Contrary to popular belief, Ford, Lincoln and Mercury vehicles do not come equipped from the factory with a standard alarm system. Instead, the Ford Motor Company equips its vehicles with a passive anti-theft system, known as P.A.T.S. If the P.A.T.S. is engaged on your Mercury Mountaineer, chances are someone either tried to steal your vehicle or tried to start it with a key that was not programmed to the P.A.T.S. transponder in your vehicle’s dash. Either way, you must reset it before you can operate the Mountaineer.

Step 1

Unlock the door and insert the programmed key into the ignition and start the Mountaineer. In most cases this will reset the P.A.T.S. system and allow you to drive away. In the event it does not, move on to Step 2. If the system is in active mode, the little red flashing light on the dash will be blinking rapidly, at roughly twice the speed of its normal, passive mode blinking rate.

Step 2

Verify that you have the correct key or try another known good key, and wait for 15 minutes to pass before repeating Step 1. At that time, the little red light should return to blinking at the slower, passive rate. If, once again, the Mountaineer fails to start, continue to Step 3.

Step 3

Raise the hood and use the battery terminal wrench, or a standard box wrench, to remove the negative battery cable. Wait 15 minutes before reconnecting the cable, then repeat Step 1. If your Mountaineer still will not start, and the flashing red light begins blinking rapidly when you attempt to start it, something is obviously malfunctioning. Either have the key reprogrammed or have more extensive troubleshooting and repairs done to the P.A.T.S. system by a certified technician.

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