Looking for expert corroboration here … re: the Prius brake problems coming to light recently. I am not an engineer. But I have raced cars with the SCCA and I do own two Priuses and a Camry hybrid so I think I have a seat-of-the-pants feel for what’s happening. Occasionally I’ll apply the brakes and the braking effort will suddenly ease for a split second. My gut tells me that the brake-empowered regenerative system, or the energy-capturing system the hybrid employs when the brakes are applied, is perhaps not being called upon at that particular split second. When I first drove our '04 Prius I was amazed at the way the brakes hauled the car down. People whom I have let test drive our cars mention thay too are impressed with the brakes. But there are tiny time periods where it appears the computer is removing the regenerative “boost” from the brakes. I have a feeling that in the model years prior to 2010, buyers of the Prius were a bit more technically savvy. You’ll notice that general advertising of the Prius did not begin until the 2010 model year. It could be that the typical Prius buyer NOW is just a typical car buyer in general and that this type of owner believes the slight “hiccup” in brake boost is a sign of impending failure. I just happen to think it is a hybrid characteristic and that it, once it is a known factor, can be lived with. Again, though, only my conjecture, and I’d like to hear other Prius owners input.
I have not driven one, but isnt the braking done by motor to recharge the battery? if so, it could just be the computer trying to catch up to the input.
Braking starts out with the electric motor, then as the car slows down to speeds too low to generate power, it switches to normal hydraulic brakes. Apparently, the problem is during the handoff from the motor to the hydraulics.
I’ve test driven the Prius before at an auto show and did not notice the problem. From what I’ve read, it usually happens on ice, when the ABS isn’t talking to regenerative braking. But Toyota says that a harder push activates hydraulic brakes.