Unfortunately, it has now happened with my 2010 Prius too. Stopped on the road to shoo animals out of rhe way... Aftrward, the warning light came on and the xar went backward when put in drive! (It DID NOT beep as when put in reverse.) I made an appointment at the dealership for first thing Monday morning. Has anyone that reports having this problem found the cause?
posible 12 volt issue? what do you mean, 'it has now happened with my 2010 prius too'? which warning light? how many miles on her?