Comment I have a 2002 Prius (Score 1) 1146
The computer went bonkers over a year ago. All the warning lights came on, etc... I bought it in South Florida, moved several times, put 140k miles on it, and live in the San Francisco Bay Area now. I took it to the Toyota dealership here and wanted an explanation!
They kept it a few months, brought in an expert, and told me it was a faulty sensor. The on-board computer thinks the hybrid battery is dead, yet it is continuously sending out a full charge! The dealership told me the faulty sensor was embedded in the transmission housing, would require a complete replacement of the transmission (which involves removing the engine), at a cost of $7,000. To fix... a sensor.
Ugh... so I opted not to fix it, as the car works great otherwise. Kinda annoying though - as every warning indicator is always lit so I never know if anything else needs service.
I gotta admit, other than that - its never accelerated on its own - thank goodness!