Garmin is the leading GPS navigation, communication and solar devices developer in the world. Among its popular products are Garmin Nüvi, Garmin StreetPilot and Garmin Zumo (for motorcyle) series of automobile in-vehicle GPS receiver and navigation unit. Garmin GPS unit allows user to update its firmware, add custom POIs (Point of Interests), Waypoints, Favorites and customize other user settings.

Most GPS navigation devices from Garmin has a reset function which allows user to access a Maintenance Mode screen with system information, diagnostic details or perform the reset function to restore Garmin Nuvi or other series unit to its original default factory settings.

Depending on which model of Garmin GPS unit you’re using, the following routine can reset the Garmin device to original factory loaded settings, or bring up the Maintenance Mode with access to System Information and View Diagnostics screen, where users can see various logs, and of course, clear all user data (reset to factory defaults) or clear Waypoints.

In order to reset Garmin device or enter into maintenance mode, perform one of the following procedures:

Power off Garmin unit. Press on continuously the upper top left corner of screen and then power on the unit by pressing once on the Power button. You should be prompted to clear all user data, or asked if do you really want to start up in maintenance mode. Press “Yes” to reset (warning: all data will be erased and lost, so backup before proceeding) or enter maintenance mode.

Hack above works on Garmin Nuvi 660, 680 series.

Turn off Garmin device. Press down on bottom right corner of the touchscreen, and then power on the GPS unit. You should be prompted whether do you really want to erase all user data, or asked if do you really want to start up in maintenance mode. Press “Yes” to reset (warning: all data will be erased and lost, so backup before proceeding) or enter maintenance mode.

Trick above works on Garmin nuvi 200, 250, 360 750, 760 series unit. In fact, there is a video demo by user of Garmin Nuvi 360 on how to perform the hidden reset function.

Note: If entering maintenance mode, it’s also possible to perform master reset by selecting clear user data option.

Once the device has been hard reset, user have to perform the set up procedure again upon start up. Note that erase user data command only delete data in the Garmin unit’s memory that isn’t accessible to the user when the unit is connected to computer. The command does not erase .gpi or .gpx files loaded (if your .gpx files contain any waypoints then they will automatically be imported into Favorites), nor will delete any MP3 music, JPG photos or any other files that have been stored on the GPS memory card.

Once the Garmin GPS unit is reseted, remember to place the device outside where there is a clear unobstructed view of the sky for 15 – 30 minutes in order for it to requires fix to GPS satellites.

Unfortunately, even if you perform master reset on Garmin GPS unit, it does not reset Garmin Lock security feature, which password-protect most Garmin electronic devices to deter theft. If you forget the PIN or password unlock code to unlock the Garmin unit, the best solution is to bring it to Garmin to get unlocked. “Secure Location” does not unlock a locked Garmin unit either as it’s only a temporary fix as when it’s turn on outside the security location, the device is locked again.