All Codes for prius 2008 - 2008 Toyota Prius

You can replace and or fix it. Before you proceed make sure that there is no open or short circuit in the fuel gauge system.

This could be related to the alternator not working as the electric system fails. How does the car run? If it is rough then it could be engine trouble, otherwise alternator or electrical drain.

Retrieve the trouble codes with suitable scan tool to reach the trouble area.

can be a few things , i'd suggest getting the OBD codes read as will point you in the direction of the problem

On this website (link below) you find fuse box diagram and description for Toyota Prius (2008)

Toyota Prius Second Generation XW20 2008 2009 fuse box diagram Auto Genius

And fuse box diagram and description for Ford Windstar (1997)

Ford Windstar 1996 fuse box diagram USA version Auto Genius

the cruise control limits have been exceeded
the rad speed drops going up hill, the transmission shifts , that exceeds the rpm so it drops back the gear s shift again and the cycle is repeated
nothing really wrong , just incorrect driving practice
good practice is to turn of the cruise control when going up hills that puts the control outside parameters for the operation

The following is from used-cars website edmunds.com ... Refer to this forum for your answer : http://answers.edmunds.com/question-Looking-to-download-an-Owners-Manual-for-an-08-Toyota-Prius-26439.aspx

I suggtes check in this link: forums/gen-ii-prius-main-forum/60662-2007-owners-manual-pdfs.

Hope this helps (remember to rate and commene this answer).

with a small flat screwdriver, remove the 2 by 2 inch black plastic covers behind the steering wheel. one of them has a hole for the cruis control lever.
loosen but dont remove the two torx screws behind these covers.
allow the airbag to fall out into your hands.
carefully raise the two yellow retainers on the airbag wires, then pull the wires away from the airbag module.
then squeeze and pull the black horn wire from the airbag.
to replace the steering wheel, unplug all the wires you see and remove the 19mm nut holding the wheel.
then by hand wiggle the steering wheel toward you.

Problem is resolved, 
I pulled & giggled a couple of fuses, found one fuse that had an extend fuse container was probably not quite seated right. Will notify dealer & replace several working fuses with new. rr