Siri can do almost anything, even start or lock your car
After developers created a proxy server between Siri and Apple to use custom commands and actions Siri can do just about everything you want it to. Take a look how one developer took proxy server and hooked it up to Viper Car system which allows him to turn his car off and on.
The “Siri Proxy” plugin I wrote handles interaction with a php script that runs on my web server. The php script, which I developed months ago for personal use, allows me to send commands to my car which has a Viper SmartStart module installed.
Current commands accepted are: “Vehicle Arm”, “Vehicle Disarm”, “Vehicle Start”, “Vehicle Stop”, “Vehicle Pop Trunk”, and “Vehicle Panic”.
Take a look at locking and arming the car alarm video below: