1. Turn off the nuvi.
2. Turn on the nuvi and hold the Power key to the left for about 30 seconds until the calibration screen appears (white screen with "Press dot").
I followed it, tried 4 or 5 times even though my fingers were already hurting from holding the power button to the left for 30 to 60 seconds each time. No dice.
I found another one from http://www.sharc.net/discus/messages/6/77.html?1236709210:
Nuvi 2xx Series: Slide the on/off power switch to the left and hold until you see the calibration screen.
Nuvi 7xx Series: Touch the screen anywhere and keep your finger there while moving the on/off switch to left (don't wait for Garmin logo to come up) and then quickly moving the switch the right (lock position). After a short while, you will reach the calibration screen. Go through the entire procedure of pressing each dot as it appears on the screen until it says "Done".
However, someone posted on this last page that the 7xx series instruction set that worked for his 255W, but he had to touch and hold at the upper left corner. I followed suit, and after more than 30 seconds, still nothing! But when I removed my finger from the screen, voila! The calibration screen appeared!
Here's the sequence of the dots that needed to be pressed as I remember:
- Lower Left
- Top Center
- Mid Right
- Top Right
- Lower Center
- Mid Left
- Turn off the Nuvi 255W.
- Touch and hold the upper left corner of the screen.
- While holding your finger at the said screen corner, slide the power switch to the left to turn the unit on, and quickly lock the touchscreen by sliding the power switch to the right even before the GARMIN logo appears.
- After a few seconds, release your finger from the screen.
- Press the dots in sequence.
