TOYOTA 2011 Sienna - Manual (Page 640)

574
3-8. Other interior features
Calibrating the compass
The direction display deviates from the true direction determined by
the earth’s magnetic field. The amount of deviation varies according
to the geographic position of the vehicle.
If you cross over a map boundary shown in illustration, the compass will
deviate.
To obtain higher precision or perfect calibration, refer to the following.
Samoa: 5 Guam: 8 Saipan: 8