BMW has the comfort access system, Mercedes has the Keyless Go system, Lexus Smart Key and so those many other manufacturers have similar setups where all that is needed to access and start the car's engine is to leave your key in close proximity. The unique sensors in it are connected to the sensors in the car’s computer system, so only your car key will be recognized. Once you approach the car just touch the inside of the door handle, and then head on in.
Approaching the Car
Once the key is within about 5 feet of the car, the system automatically senses it’s within range. Your car will verify the key, so you just have to touch the door handle to unlock it.
Start and Drive
The car is either engaged or disengaged based on the presence of the matched key signal. Once in the driver’s seat, the driver uses the Push button to start and stop the engine.
How do they overcome the keyless system?
This might be all convenient in the perfect world, unfortunately we live in a world with scum and low lives wanting to steal want does not belong to them. So what happens is thieves using wireless signal amplifiers to obtain and boost the signal from the key in your house and uses that to open and start the car.
Solution and Prevent Theft
This can be all avoided by tempory placing your keys in an empty tin can which you might have lying around the house, but in the long run we highly suggest you invest in a faraday bag that is purposely built to block any external signals avoiding theft such as seen in the video.