Are you sure your car has the factory alarm system? Look at the button bank & see if one of the buttons on the right side has an icon of a tow truck towing a car. If you have that button, your car has an alarm. If you car doesn't have an alarm, your fob will still have a red panic button that should sound the horn when depressed. I believe those cars equipped with the factory alarm also activates the horn when the panic button is depressed. The horn for the alarm is separate and much higher pitched.