"security" light on

[alenstein]

I have a '93 TA with LT1, my "security" light comes on just few seconds after start up and stays on. Twice the car wouldn't start. Any ideas?

[tabahr]

The system that you are dealing with is the VATS. Vehicle Anti Theft System.

There is a resistor pellet on your ignition key. When you insert the key, the VATS module looks at the value of that resistor and if it is the correct value, tells the PCM it is OK to start.

Often times the key will get dirty and not show the proper resistance. Try another key. Also the contacts inside the ignition cylinder wear out and cause a no-start situation. What happens, is the VATS module cannot see the key because there is no contact in the lock cylinder. If this is the case, replace the lock cylinder.

To test this, Measure the resistance value of your key with a meter and record it. Next, locate the 2 VATS leads that go up the steering column and intercept them. Splice in a resistor of the same value of the key and test (or use the key itself). The car should start and run, with no error light. If the car will not start, or there is still an error light the problem is most likely the VATS module, a broken wire somewhere or a bad ground. (I'd hope it is the key or the lock cylinder)

Here is a chart of the pellet codes and values:
http://shbox.com/1/4th_gen_tech2.html#pass_key

Here is a picture of a VATS module, although I do not know where they are mounted in our cars.
http://www.tacreationsusa.com/images...SBox.JPG<br />

Here are tips on Locating V.A.T.S. Wires:

Be carefull of the airbag wires.....
V.A.T.S. wires are very small, usually 22 AWG. They are always found together in a small tube. This tube, wires inside and all, is still only about 14 AWG in size. This little tube will have a ridge up the middle because it has the V.A.T.S. wires molded inside. Usually the tube is WHITE or ORANGE, although in some older cars, it will be BLACK. The V.A.T.S. wires run right down the steering column from the ignition key cylinder. After that, they head over to the V.A.T.S. module, found behind the glovebox in many cars.

[alenstein]

Thank You, I'll try the tips, and keep you posted.