What is PATS key - Okey DoKey Locksmith
A PATS key is a transponder-equipped automotive key used with Ford Motor Company's Passive Anti-Theft System. PATS, also known as SecuriLock, was introduced on selected Ford, Lincoln, and Mercury vehicles beginning in the 1990s as an electronic immobilizer system designed to prevent the engine from starting without an authorized key.
The plastic head of a PATS key contains a transponder chip with electronic identification information. When the ignition is turned on, the vehicle checks for a recognized transponder before allowing the engine to start.
This means that making a replacement PATS key can involve two separate operations: the blade must be cut for the vehicle, and the transponder must be programmed to the immobilizer. A mechanically correct key may turn the ignition but still fail to start the engine if its transponder is not recognized.
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What Is Ford PATS?
PATS stands for Passive Anti-Theft System. Ford also uses the SecuriLock name in connection with its passive vehicle anti-theft technology.
The system is considered passive because the driver does not normally have to arm or disarm it manually. Instead, authorization takes place as part of the normal starting process when the vehicle detects the transponder contained in the key.
PATS appeared on selected Ford Motor Company vehicles and was subsequently used across numerous Ford, Lincoln, and Mercury models.
How Does a PATS Key Work?
A PATS-equipped vehicle uses electronic communication between the transponder in the key and the vehicle's anti-theft system.
When the ignition is operated, the vehicle attempts to identify an authorized transponder. The chip in the key responds electronically, and the vehicle determines whether the key is recognized by the PATS system.
If the correct transponder information is recognized, the system allows the normal starting process to continue. If the key is not recognized, the engine immobilizer can prevent the vehicle from starting even though the mechanical blade fits and turns the ignition.
The entire exchange happens automatically, which is why a driver using a properly programmed key may never notice the anti-theft verification taking place.
What Does a PATS Key Look Like?
Many PATS keys resemble ordinary automotive keys with a plastic head. The important difference is hidden inside that head: an electronic transponder.
You cannot reliably determine whether a key contains the correct transponder simply by looking at the outside. Replacement keys must match the applicable vehicle and PATS system.
Later Ford keys may combine several technologies in one housing, including the mechanical blade, immobilizer transponder, and remote-entry buttons.
PATS I, PATS II & Later Systems
Ford's PATS technology changed as it was introduced across additional vehicles. Two terms commonly encountered with earlier applications are PATS I and PATS II.
An important practical difference involves adding another key. Earlier PATS I applications may allow an additional key to be added when one working programmed key is available. PATS II applications generally require two working programmed keys for the owner-performed spare-key procedure.
Later Ford vehicles continued to use more advanced versions of immobilizer technology, including systems using encrypted transponders.
Because Ford used different systems across years and models, do not select a replacement key or programming procedure based only on the vehicle manufacturer. The exact year, model, key type, and anti-theft system matter.
How to Duplicate a PATS Key
Duplicating a PATS key involves more than copying the blade. A complete working duplicate generally requires both:
- A correctly cut mechanical key blade
- A compatible transponder recognized by the vehicle
If you already have working keys, making a duplicate car key before one is lost can simplify the process considerably.
The replacement blank must first be compatible with the vehicle. The blade can then be cut to match the vehicle's mechanical lock, and the transponder can be added to the vehicle's authorized-key system using the applicable programming procedure.
Replacement Ford transponder keys may be available through automotive locksmiths, dealerships, and online key suppliers.
PATS Key Programming
The programming requirements depend on the PATS version and vehicle application.
On certain PATS I applications, one existing programmed key may be sufficient to add another compatible key. On many PATS II applications, the owner-programming procedure requires two separately programmed working keys before an additional key can be added.
This distinction is important. Having one working key does not necessarily mean that every PATS-equipped Ford can add another key through an onboard procedure.
If the required working keys are not available, specialized key-programming or diagnostic equipment may be necessary. An automotive locksmith or Ford, Lincoln, or Mercury dealer may be able to perform the programming for a supported vehicle.
What If All PATS Keys Are Lost?
An all keys lost situation is different from making a spare while working keys remain. There is no existing key available to duplicate, and an owner-performed spare-key procedure that depends on existing programmed keys cannot be used.
A replacement key must have the correct blade cuts and a compatible transponder, and the vehicle must be made to recognize the replacement key.
Depending on the vehicle, a locksmith or dealership may use vehicle-specific information to originate the mechanical key and appropriate equipment to perform the required immobilizer programming.
If you have lost every key to your Ford, Lincoln, or Mercury vehicle, see our car key replacement information for additional replacement options.
Common PATS Key Problems
A vehicle that cranks incorrectly or refuses to start does not automatically have a defective key. However, when a PATS-related problem occurs, the vehicle may fail to recognize the transponder and prevent normal starting.
Possible key-related situations include using an unprogrammed replacement key, using an incompatible transponder, or having a damaged key.
If you have another known working PATS key, comparing the behavior of both keys can help distinguish a problem affecting one key from a problem affecting the vehicle or anti-theft system.
The mechanical and electronic portions should also be considered separately. A blade that no longer turns smoothly may indicate a mechanical key or ignition problem, while a key that turns correctly but is not electronically accepted may involve the PATS system.
PATS I Equipped Vehicles
The following are PATS I applications from the original vehicle information for this guide:
- Ford Contour V6 Duratec — 1998
- Ford Mustang — 1996–1997
- Ford Taurus LX and SHO — 1996–1997
- Ford Expedition — 1997–1998
- Lincoln Mark VIII — 1997
- Mercury Mystique LS — 1998
- Lincoln Navigator — 1997–1998
- Mercury Sable — 1996–1997 (not all vehicles)
PATS II Equipped Vehicles
The following are PATS II applications from the original vehicle information for this guide:
Ford
- Ford Mustang — 1998–2007
- Ford Taurus LX, SE and SHO — 1998–2006
- Ford Explorer — 1998–2007
- Ford Expedition — 1999–2006
- Ford Excursion — 2000–2005
- Ford Escape — 2001–2006
- Ford Focus — 2000–2007
- Ford Ranger V6 — 1999–2004
- Ford F-150 and F-250 LD — 1999–2014
- Ford Contour V6 — 1999–2000
- Ford Windstar — 1999–2004
- Ford Thunderbird — 2002–2005
- Ford GT — 2005–2006
- Ford Five Hundred — 2005–2007
- Ford Fusion — 2006 and later
- Ford Freestyle — 2005 and later
- Ford Freestar — 2004 and later
- Ford Figo — 2010
Lincoln
- Lincoln Aviator — 2003–2005
- Lincoln Blackwood — 2002–2003
- Lincoln Mark LT — 2006
- Lincoln Continental — 1998–2002
- Lincoln Navigator — 1999–2006
- Lincoln Town Car — 1998–2006
- Lincoln LS6 and LS8 — 1999–2006
- Lincoln Mark VIII — 1997–1998
- Lincoln Zephyr / MKZ — 2006
Mercury
- Mercury Mariner — 2005–2006
- Mercury Marauder — 2003–2005
- Mercury Cougar — 1999–2002
- Mercury Grand Marquis — 1998–2006
- Mercury Milan — 2006
- Mercury Mountaineer — 1998–2007
- Mercury Montego — 2005–2006
- Mercury Monterey — 2004–2006
- Mercury Mystique LS — 1999–2000
- Mercury Sable — 1998–2005
PATS Key FAQ
What does PATS stand for?
PATS stands for Passive Anti-Theft System, Ford Motor Company's immobilizer technology used on many Ford, Lincoln, and Mercury vehicles.
Is a PATS key a transponder key?
Yes. A PATS key contains a transponder used by the vehicle's immobilizer system. The transponder must be recognized before the vehicle is permitted to start normally.
Can a PATS key be copied?
The blade can be mechanically duplicated, but producing a complete working replacement also requires a compatible transponder that the vehicle recognizes.
Can I program a Ford PATS key myself?
Some applications provide an onboard method for adding another key when the required number of already programmed keys is available. The requirements differ between PATS systems and vehicle applications.
Why does my new key turn the ignition but not start the car?
A mechanically correct key can turn the ignition even if its transponder is incompatible or has not been properly added to the PATS system. Both the mechanical blade and electronic authorization must be correct.
What happens if I lose every PATS key?
A new key can still be made, but the process is more involved because there is no working key available for duplication or owner-performed programming. Professional key origination and programming may be required.
