Car thinks it has a security system

About once a week our 2001 Malibu refuses to start until the cars security system is re-set by leaving the switch on for 10 minutes, then it allows the car to start. Only problem is there is no security system on the car.

Are you the original owner?

No, it had about 35,000 miles on it when we got it and now has 185,000

What leads you believe there is no security system in the vehicle?

If you have an ignition key WITHOUT a chip in it, then you have no security system.

I’m thinking the previous owner may have installed one, perhaps an aftermarket type.

No, I’m sure it doesn’t have one. The “security” light periodically comes on and then soon after the problem hits. We use the re-set instructions in the Owner’s Manual and then it will start. The car doesn’t have remote keyless entry but after we lock the car and close the door, the lights will flash and the horn will honk as if we had hit the lock button on a remote.

Why are you sure there is no security system? It would be unusual for it not to have one. Do you have the window sticker and does it say security was deleted?

Just going by what the dealer told us, but he could have been wrong. Question however is if it does have one, how could we set it? There is no apparent way to do that? We bought the car in '03 and this problem has only been going on for the last year. Problem is that it is getting more and more frequent? If it does have a system, what could be triggering it?

Normally, the engine lock out type security is passive. That means that it is always armed, and only disarms when the correctly coded key is inserted.
Perimeter type alarms are normally armed when you lock the doors (with the key off).
It sounds like either the key or the part that reads the key has a problem.

Sounds like trip to Chevy dealer for either new keys or ignition switch. Thanks for your help.

Sounds like a trip to a Chevy dealer for new keys or new switch.
Thanks for you help.