Intro to VATS Keys
Before the days of TRANSPONDER KEYS and computers in cars, GM introduced VATS (Vehicle Anti-Theft System) keys. Instead of a computer chip programmed to the car's computer, they attached "transistors" to keys and the car would measure the OHMs of the transistor before allowing the car to start.
Note that VATS is quickly disappearing. Just 5 years ago, we used to sell more than a 1000 VATS keys every month. Now it's less than half of that. Those old GMs just aren't on the roads anymore, thank God. But you still need to know about them.
There are 15 "VALUES" of VATS keys
GM randomly assigned one of 15 different values to each vehicle and then attached the matching transistors onto the car's keys.
Note that over the first couple of years, GM realized that VATS value #1 was problematic and stopped using that value. This is the reason the VATS value #1 key is hardly ever purchased.
How do we know the VATS value?
If you have a working key, you can simply measure the resistance value using a multimeter and this chart.
| VATS Value |
Resistance Value (ohms) |
VATS Value |
Resistance Value (ohms) |
VATS Value |
Resistance Value (ohms) |
|---|---|---|---|---|---|
| 1 | 402 | 6 | 1470 | 11 | 4750 |
| 2 | 523 | 7 | 1870 | 12 | 6040 |
| 3 | 681 | 8 | 2370 | 13 | 7500 |
| 4 | 887 | 9 | 3010 | 14 | 9530 |
| 5 | 1130 | 10 | 3740 | 15 | 11800 |
Some VATS decoders also include a "key decoder" feature that allows the locksmith to simply insert a key and the tool displays the VATS value. Watch the video below for a better understanding:
If you don't have a working key, there are 3 ways to find the VATS value:
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Buy a key code from GM Although this can be the fastest and easiest method, this can cost almost $50. Also, not every locksmith has access to key codes. If you are tight on time and/or have other jobs to get to, this can often be the best choice.
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Try every key Nobody really does this, but it is a valid method and discussing it will help to understand how VATS really works in practice. STEP #1: Pick a key with any value, let's say we start with #2. Cut the key. STEP #2: Turn the key in the ignition. You have a 1-in-15 chance the car will start. STEP #3: If the car doesn't start, wait 4 minutes and then try again with the next value. One of the keys will work, 14 of the keys will not. It could be a fast process if you're lucky or could take 60 minutes (4 minutes x 15 keys) if you're not. Do you feel lucky today?
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Use a VATS Interrogator There are tools like the Aerolock VAT1 VATS Interrogator ($125) that can trick the car into thinking you're inserting a real VATS key with a transistor chip. The time it takes for this method is the same as trying every key (#2). Just turn the dial on the tool, cross your fingers, and try to start the car. You must still wait 4 minutes between tries and you still only have a 1-in-15 chance each time you try, but at least you're not wasting keys.
There are 3 different "types" of VATS keys
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Single-sided This was the first generation, a small key with only 6 cuts on one side. These started in the late 80s, but all vehicles started moving towards double-sided keys soon after.
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Double-sided This was the second generation, a longer key with a small head and 10 cuts on both sides. These started coming out in the early 90's.
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Corvette big-head Corvette owners are snooty and need special, more expensive keys with Corvette logos. Or maybe they're just weak people and need a bigger head to hold onto. The blade is exactly the same as the standard double-sided VATS key, so you can actually use the cheaper, smaller key, but your Corvette owner will not be happy. I told you, they're snooty.
