98 Buick Lesabre Security light on

[pavlosgian]

Today Dec. 18/03 for the first time I couldn't start my car. I tried again after a few minutes and it started but the security light is on all the time. I turned off and on my car afew times without any trouble but again the security light is on all the time.
Any help will be appreciated very much
Thank you
Pavlos

[joshey]

your key has a battery in it, replace the battery and see if that helps

[Flatrater]

Originally Posted by joshey

your key has a battery in it, replace the battery and see if that helps

Where do you get your mis-information from?

[avatar307]

If I'm not mistaken that has to do with the PATS system installed on your car. All GMs after 96 have a PATS or PATS-II system in them. It works by "reading" the resistance of a resistor embeded in your key to see if it matches the known value. (The resistor is the like shine metal piece surrounded by black plastic on the shank of your key.) If the security light is staying on all the time, that means it is in fault mode. Meaning when you insert your key, the system cannot "read" the resistor on your key to tell if is the right key or not. Thus the system goes into fault mode and let you start the car.

The first time you attempted to start it, it likely read the resistor and got the wrong resistance from it. This cause the system to go into a lockout mode and not allow the engine to crank or the fuel pump to run. It then locked out any attempt to start the car for a certain number of minutes before reseting. (I cannot remember if there is a certain number of tries before it locks out, or how long it locks out your car. It's some really arbitrary number, like 18 minutes.)

Anyway, long story short (yes, this is short for me) you need to replace the sensor inside the keyway... which will mostly mean replacing the whole cylinder. Alternatively, you can trace down the sensor wires, cut them off, and splice in a resistor exactly matching that of the resistor in your key.

-C

P.S. Yes, I know I spelled resistor wrong.

[Grumpybear]

Avatar, do you know how to "trace the wires?" That is a daunting task for this Texas trained engineer (mechanical engr. not elec.). The dealership told me there is a wire in the trunk that can be disconnected, but where? Thanks.

[Flatrater]

Avatar its called the VATS system only one version the other systems in use by GM are the Passkey and Passkey 2 systems. Vats uses a resistor and Passkey uses a Hall effect switch, Passkey 2 uses a transponder embedded into the plastic case.