Toyota 2006 Prius Owner's Manual page 133

If the indicator comes on...
(a)
(b)
(c)
(d)
or
(e)
(f)
(g)
Stop immediately and contact Toyota dealer.
Stop and check.
Stop and check.
Take vehicle to Toyota dealer.
Take vehicle to Toyota dealer immediately.
Take vehicle to Toyota dealer.
Take vehicle to Toyota dealer.
Do this.
133