From the files section in this group; under frequently asked questions (FAQ),
then navigation:

How do I get into the diagnostic screens?

Start the Prius.

While pressing and holding "INFO" switch, operate light control switch, OFF,
TAIL, OFF, TAIL, OFF, TAIL, OFF.
The diagnostic mode starts and the service check screen ("System Check Mode")
will be displayed. Service inspection starts automatically and the result will
be displayed after a short pause.

You'll be able to see how many satellites are currently being received as well
as Greenwich Mean Time, among other things.

Press "Menu" to see the menu.
To exit either turn the power switch off,
or press the "DISPLAY" switch for 3 seconds.


--- In Prius-2G@yahoogroups.com, Christofer Arroyo <ckarroyo@...> wrote:
>
> Could you please post how to get to the diagnostics screen?
I have a 2009 Prius and the one method I've seen on how to do this did not work
for me.
> Thanks,
> C.