There have been a few complaint's about the Z1/Z2 owners about there navigation unit rebooting during driving since it's Hdd Based (harddrive). The problem was first noticed when I received my unit back in Sept 06. I have contacted Pioneer Tech surport and went into a lot of detail resolving the problem. Pioneer has a patch surport and I highly advise Ts member's to receive this Update.
(Link Provided)
http://www.pioneerelectronics.com/PU...Freezing+Issue.
Right now I am helping a Ts member get his Z2 on his crewmax from the same problem's my unit once had. I'll post some picture showing the update's on the Navi screen and what to look for in your service screen menu to insure you have the lastest updates.
Cheer's Erik..