Many upgrades are available to the buyer of a Lexus IS 250. One such upgrade is a GPS navigation system that may benefit drivers who are travelling on unfamiliar roads. The navigation system allows drivers to receive accurate, turn-by-turn directions to almost any North American address. Once per year, navigation map updates are released for Lexus systems. As of November 2010, these updates are priced at £129 and can be purchased from your Lexus dealer on a DVD.
Determine what generation of vehicle hardware your IS 250 uses. Cars manufactured from 2006 to 2009 use generation five, while 2010 models use generation six.
Go to your nearest Lexus dealer (see Resources) to purchase the update DVD. Notify the dealer whether you need a generation five or six update.
Turn the IS 250's ignition switch to the "On" or "ACC" position, then apply protective tape to the bottom left, bottom right and middle of the navigation system dashboard.
Insert two 1.5 Phi or less precision screwdrivers into the holes located on each side of the clock. Screwdrivers with a higher Phi measurement have a higher magnetism, which may damage the electrical components of the system.
Cover another screwdriver with protective tape, and insert it into underneath the hazard switch, located directly between the two clock holes. Remove the two precision screwdrivers from the holes.
Press the "Menu" button on the navigation system, then touch "Map DVD." Touch "Eject DVD" to remove the old map disc. Insert the new map DVD. The update occurs automatically.
Remove the screwdriver from the hazard switch, then remove the protective tape.
If you are uncomfortable updating the system, your Lexus dealer can do it for a fee.