Known as Garmin Lock, this feature works by requiring the user to input a four digit PIN number before the GPS becomes operational. Meaning, the PIN code is required to start-up and use the device. Without the PIN the GPS receiver is just another electronic paperweight. Although this doesn't prevent the GPS from being stolen, it is a security feature that prevents the theif from getting your personal information and other pertinent data from your device.
Garmin Lock has another feature -- the Secure Location. The secure location enables you to access the GPS without entering the PIN (in case you forget it). The secure location is not really a security feature in the real sense of the word. It is a bypass to the security of the Garmin Lock itself. But even with the secure location, the forgotten PIN could not be reset. So make sure never to forget this PIN code when considering on enabling this feature.
With that, how do you enable these features? On the GPS main screen tap the wrench (Tools), like below. Then System (on the leftmost part of the next screen).
Security should be at the bottom part of the screen, so scroll down once and it will be there. The instructions here are for a Garmin nuvi 255W, but should not differ much on your unit.
You will then see Garmin Lock and Safe Mode. Those two are Off by default. Turn Garmin Lock on and input the PIN code twice. For Safe Mode, set a Secure Location and it will turn on.
I hope this helps you protect personal information on your Garmin GPS from theft in the event your GPS unit gets lost or stolen.
