VATS (Vehicle Anti Theft System) was introduced by GM on the 1986 Corvette because the Corvette had become the number one target of car thieves. Corvette thefts dropped so impressively after VATS was implemented that GM expanded the system in 1988 to the Camaro , Firebird, and Cadillac Seville...
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VATS (Vehicle Anti Theft System) was introduced by GM on the 1986 Corvette because the Corvette had become the number one target of car thieves. Corvette thefts dropped so impressively after VATS was implemented that GM expanded the system in 1988 to the Camaro , Firebird, and Cadillac Seville. Before long, VATS was standard equipment on all Cadillac vehicles and on many other Chevrolet, Pontiac, Buick, and Oldsmobile vehicles. As the system was added to more vehicles, GM began using the terms “PASSkey-1” and “PASSkey-2” as more descriptive names for the system. From the locksmith's point of view, there is no functional difference between VATS and PASSkey-1 or PASSkey-2, and most technicians still refer to the system simply as VATS.
The system itself operates on a very simple principal. In addition to the standard sidebar ignition, there is a resistor embedded into the key. (See photo 1) When the key is inserted into the lock and turned, an electrical current runs through the resistor. The amount of current drop caused by the resistor is measured by a computer. If the current drop matches the pre-set value stored in memory, the car is allowed to start. If the current drop is higher or lower than the pre-set value, the vehicle will be prevented from starting – even with the correct key – for several minutes. No alarm sounds and the only indication that the vehicle has been disabled is an indicator on the dash.
The time delay feature was the main reason that VATS proved so successful. Studies showed that if a would-be car thief could be slowed down, even for a few minutes, he or she would look for an easier target. VATS-equipped vehicles soon became some of the least stolen vehicles on the road. The insurance companies went from charging a surcharge for owing a Corvette to offering a discount on the Corvette or any other vehicle that was equipped with the VATS system.
What Vehicles are Equipped with VATS?
VATS was used strictly on GM vehicles, and a list of vehicles is shown in Chart 1 along with this article. As you can see, the number of vehicles equipped with the VATS system peaked in the late 1990s, as transponder systems and other anti-theft systems were developed. The last VATS-equipped vehicle sold was the Chevrolet Camaro and Pontiac Firebird which were both discontinued after the 2003 model year.
How do I duplicate a VATS key?
Originally 15 different resistor values were chosen for the VATS system. These values are numbered 1 – 15, with the number one key having the least resistance and the number 15 key having the most resistance. Due to technical problems involving the system's ability to accurately read the very low resistance of the number one key, the number one value was discontinued on new vehicles in the 1989 model year. When the system was implemented on the newer 10-cut locks in 1995, only 14 values were used on the double-sided keys.
Duplicating a VATS key requires two steps. First you must read the resistance value of the customer's key and then duplicate the cuts on the correct key blank. The resistance value of the key can be determined with a simple volt/ohm meter, but most locksmiths use a device known generically as a VATS interrogator to determine the resistor value of the customer's key. If you chose to use a volt/ohm meter, you will need a conversion chart such as the one shown in Chart 2 to convert the ohms reading from the meter into the resistor value for the key. When reading a key this way, you will need to bear in mind that actual reading that you get from the key may vary by as much as 3 percent from the “Target Value.” This variation is built into the system in order to make it easier to operate.
Most VATS Interrogators automatically compensate for the 3 percent plus or minus variation allowed in the keys and simply give you a numerical value of one through 15 when the key is inserted into the unit. (We'll discuss VATS interrogators in detail later.) Once you have selected a key blank with the same resistor value as the customer's original, all you have to do is duplicate the key as you would any other GM key.
The VATS-operated security system uses a modified ignition lock and key with a resistance pellet mounted into the shoulder.
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