After a National Highway Transportation Agency investigation into sudden stalls reported by Toyota Prius owners, Toyota has initiated a worldwide recall of 160,000 of the cars. Affected cars are from 2004 and early 2005. Toyota calls it a Voluntary Special Service Campaign, which will amount to a firmware upgrade at the dealership. The problem stems from a programming error that can activate all the warning lights, causing the car to think its engine has failed. The car enters a fail-safe mode in which it runs under electric power only, giving the driver enough time to pull over to the side of the road.
Although some people might assume the complexity of the Prius allows for such problems, I look at it as a testament to the safety of having an extra power train onboard. If a normal car has catastrophic engine failure, you're lucky if you can coast off to the side of the road. With the Prius, you're not going to be stalled in the middle of the freeway, stopping traffic for miles.