How to find vats resistance without key?

Method #1:

1. Use a multimeter to measure the Ohms value of the thin strip of metal on the plastic oval on the keyblade of your key. Place both probes of the multimeter on the strip while testing.
2. Choose the Resistor that most closely matches the Kilo-Ohms value of your key's chip.
3. Use your vehicle's Year, Make, and Model to find the correct key shape, then order the correct chip number for your key's Ohms value.

Resister value chart

Method #2:

1. Locate the vehicle's VIN.
2. Call your local GM dealership parts counter and give them the VIN to check which part number is the correct one for your vehicle or what the resistor value is.
3. If they give you the part number then order by part number. If they tell you the resistor value then do a Year, Make, Model search on our website and choose the VATS key with the resistor value that you need.

VATS Backstory:

VATS (Vehicle Anti Theft System) came out from GM on the 1986 Corvette because Corvette became the number one target of car thieves. Corvette thefts decreased drastically from VATS. GM started putting VATS on Buick, Cadillac, Chevys, and Pontiac Oldsmobile vehicles. As the VATS system was added to more models, GM began calling it PASSkey-1 and later, PASSkey-2. There isn't a functional difference between VATS and PASSkey-1 and PASSkey-2.

In addition to the standard side-bar ignition, there is a resistor embedded on the key. When the key is inserted into the lock and turned, an electrical current runs through the resistor. The amount of current reduction caused by the resistor is measured. If the current reduction matches what the vehicle's system expects, the car is allowed to start. If the current reduction is higher or lower than what the vehicle's system expects, 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 stopped so many thefts. The longer it takes a theif to steal a car, the more likely he'll be spotted, photographed, or arrested.