Mazda 2008 MX-5 Miata Owner's Manual page 424

Navigation Set Up
This function allows you to correct any error in the position or direction of your vehicle display.
Before Steps
Adjusting Current Position and Direction
select
ENTER
Open the [Calibrate Position] screen
Distance
This function automatically corrects any error in the display of the current
position that might occur after tire replacement.
select
ENTER
You will have to drive about 6 miles (10 km) before distance correction is complete.
24
select
MENU
ENTER
ENTER
Move to the correct position and select
Use
or
heading, and select
ENTER
to adjust the direction in which you are
.
Calibration
.
ENTER