The 2010 Prius may have an issue with the regenerative braking system. I own a 2010 Prius IV and sudden loss of brakes has happened once. I’ve driven the car 8,000 miles so far. This is my reply to a priuschat.com thread where several Prius owners were discussing the issue.
From 12-18-09:
“I experienced this on my IV last week. To make a right turn, I started braking just as the front wheels hit a bump on the road. Braking power was not there with the usual pedal pressure. It was like the breaks became very weak. It lasted for about 1/2 second and then it started to brake as usual. I may have increased the pedal pressure to force this. I almost missed the turn. No other incidents since or before. I will try to replicate the event under safe conditions.”
