One problem related to tire pressure light on has been reported for the 2008 Toyota Prius. The most recently reported issues are listed below.
I had a sudden blow-out while driving my 2008 Prius on the freeway. All four tires are goodyear p185/65r15 and came with the vehicle. The car mileage is about 19,900. Without any warning (low tire pressure light, etc. ), the left rear tire blew out due to tread separation almost causing me to lose control of the vehicle. I went to the local Toyota dealership who described the damage to the tire as "tread separation" on their paperwork. They replaced the tire as a "one time customer courtesy" but would not acknowledge it was defective. I am now very concerned about the remaining three tires on the car.