OK, I need to order a couple of keys for Marco. We used to have a machine at work that measured VATS resistor values, but it seems to have vanished over the years. But....my tech happened to find the resistance values so you can measure your VATS keys with an ohm meter and know which key you need (1-15).

Sooooo....I figured I would post them in case anyone needs to figure out which VATS key their car uses without having to go to the dealer. The time to do this would be BEFORE you lose your keys.

For your perusal.....

Key #1 = 0.41 K Ohms resistance
Key #2 = 0.53
Key #3 = 0.68
Key #4 = 0.89
Key #5 = 1.13
Key #6 = 1.47
Key #7 = 1.87
Key #8 = 2.37
Key #9 = 3.02
Key #10 = 3.73
Key #11 = 4.76
Key #12 = 6.05
Key #13 = 7.47
Key #14 = 9.55
Key #15 = 11.76

Hope someone finds this of value.

 

 

Are those the only values?

 

There are only 15 possible first generation VATS keys.

 

Yes , but there are design tolerances so your key may not be exactly that value.
The VATS module will accept a resistance within the range shown below for a given key #

 

Good info.

To expand on it, in the interest of additional detail for those who aren't familiar with the system:

The pellet in the ignition key is just a resistor. You can read the resistance of the pellet with a common ohm meter. To do this, set your meter to the Ohms scale, and place the tip of one probe on either side of the pellet in the key. Keep your fingers away from the metal portion of the probes and the pellet so that the meter is reading only the resistance of the pellet, and not the resistance of your body also. Read the resistance on the meter.

The Vehicle Anti Theft System (VATS) reads the resistance of the pellet when the ignition key is in the switch. If the resistance is wrong, the starter relay will not engage (engine won't crank), and the fuel injectors will not be triggered (engine won't run if push-started or hot-wired).

There are 15 different codes/values:

VATS Pellet Code, Nominal ohms value, Low end of ohms range, High end of ohms range

1, 402, 386, 438

2, 523, 502, 564

3, 681, 654, 728

4, 887, 852, 942

5, 1130, 1085, 1195

6, 1470, 1411, 1549

7, 1870, 1795, 1965

8, 2370, 2275, 2485

9, 3010, 2890, 3150

10, 3740, 3590, 3910

11, 4750, 4560, 4960

12, 6040, 5798, 6302

13, 7500, 7200, 7820

14, 9530, 9149, 9931

15, 11800, 11328, 12292

If the CCM reads a resistance value that's outside of the range that it expects to see (below the low end, or above the high end), the VATS system will disable the starter and injectors. Keep the contacts on your keys clean, and free of corrosion. If they get nasty, the resistance will go high, and the gunk on the contacts will migrate to the mating contacts in the ignition lock cylinder, making a mess of them as well. I make a habit of always wiping the key contacts on my pants leg (unless it's sweat-soaked) before putting the key in the switch.

Be well,

SJW

Edit: Sorry for the duplication. Previous response from Rodj arrived while I was typing this one up.

 

Great post and informative.