VATS and PASSKey I/II, one of the pioneer anti-theft systems, is slowly coming to its end. For the 2005 model year, only one General Motors vehicle, the Buick Century, will be equipped with the resistor pellet in the key-based anti-theft system. That is for the non-fleet sales of General Motors...
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VATS and PASSKey I/II, one of the pioneer anti-theft systems, is slowly coming to its end. For the 2005 model year, only one General Motors vehicle, the Buick Century, will be equipped with the resistor pellet in the key-based anti-theft system. That is for the non-fleet sales of General Motors vehicles sold in the United States. For the purpose of this article, we will use the term VATS to describe the resistance pellet-based anti-theft system. The term VATS is the acronym for Vehicle Anti-Theft System.
The VATS key-operated security system uses a modified ignition lock and a key with a resistance pellet mounted into the shoulder. The anti-theft system's requirements are two parts. First, the cuts in the key must be correct to operate the mechanical lock. Second, the resistance pellet must match the resistance value of the electronic system to operate the car. The security system is invisible; the operator of the car does not have to do anything special to either turn on or off the system.
The components of the anti-theft system which affect locksmiths are the keys and the ignition locks. Each key has a resistor pellet secured into the shoulder between the bitting and the bow. The ignition lock has two contacts built into the plug which make contact with the key's resistor pellet, completing a circuit. In order to operate the vehicle, the resistance read from the key's pellet must match the resistance value for the ECM (anti-theft) module.
The original system was designed to have a total of 15 different resistance values. This way, every VATS-equipped car would have the option of using one of the 15 values. Over the years, the first value was eliminated, reducing the number to 14. Even with 14 values, the average time to decode the system is 30 minutes to one hour.
When a VATS key is inserted into the ignition and turned to the "Start" position, several things happen. An ignition signal is received at the module. In turn, the module sends out current through the wiring to the resistor pellet in the key and back to the module. If the resistance value matches, the relay in the starter circuit activates, permitting the starter to operate. At the same time a second coded signal is sent to the ECM, enabling the fuel system to operate. The engine will then be able to start and run.
If a correctly cut key with an incorrect resistor pellet attempts to start the car or a thief attempts to force the lock, the starter motor and the fuel system will not activate. When a wrong resistance value is tested, the system has a down time of between three and four minutes. This means that after each wrong key tested, the wait period is three to four minutes. Less than four minutes is possible if the instrument panel in the car counts down the time.
In 1986, when the system was introduced, the keyway for the VATS-equipped vehicles was the single-sided key with the "A" keyway. The VATS key blade is slightly longer than the standard "A" keyway key. The code series for all single-sided VATS equipped cars is the same as for non-VATS equipped vehicles. However, no matter the code series, the single-sided VATS key always is the "A" keyway. The double-sided VATS key was introduced for the 1995 model year. The double-sided VATS key blanks are the standard car key with the pellet. The VATS-equipped cars use the same key codes as the non-VATS-equipped vehicles.
General Motors tool suppliers and several locksmith tool companies began introducing "Interrogator" Tools, designed to interrogate the car's electronics to determine the resistance pellet value. The "Interrogator" Tools would connect to the two lead VATS wires at the base of the steering column. The purpose of these tools was to separate the mechanical from the electronic systems. This eliminated the need to cut VATS keys with different resistance pellets to the same bitting in order to test the system. Then, a mechanical key could be used to operate the ignition lock and the "Interrogator" Tool could provide the resistance value in order to start the engine. To test the system, the ignition had to be rotated to the "Start" position.
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...
The PassLock system was designed to prevent vehicle theft by disabling fuel to the engine if attempts are made to start the vehicle without the correct bitted key.
All four use the GM Z-Keyway system and the “Circle Plus” transponder system. All can be programmed with the standard GM on-board programming procedure, which takes 30 minutes.