NHTSA Complaint #11683582 — 2010 TOYOTA PRIUS

It is a known problem that Priuses manufactured from 2004 to 2015 have issues with the brake master cylinder and brake booster accumulator. When the vehicle computer recognizes an internal leak (ABS C1391) or other issue in the accumulator pump, it completely disables the regenerative braking system, which significantly reduces braking power. In my case, the problem is intermittent, and the vehicle computer will occasionally clear the code and operate normally. A slight whirring sound can still be heard (indicative of an internal leak), leading me to conclude that the part is still damaged, even when the code clears itself. This continues to affect my and my passengers' safety because the problem comes back with no warning while driving. Many times at highway speeds, the regenerative braking system will shut off while decelerating. This has caused scares and near-accidents. Imagine you are approaching stopped traffic while traveling 65 miles per hour. You press the brake to start slowing down, and while decelerating, the dashboard lights up and the brake pedal goes spongey. Now, you must slam the brake all the way into the firewall to engage the disks and pads exclusively. Aside from the imminent terror of hitting the car in front of you, now you are skidding on the brakes, worried the car behind you will crush the rear. Sooner or later this will cause somebody to get into an accident when a split-second decision cannot to be made quickly enough. The issue is well-known, and a warranty recall was issued, but it does not cover any vehicles over a certain age and mileage. It has been reproduced by my local mechanic and inspected by a Prius specialist, who both quote about $3800 to fully replace and recalibrate the failing parts. There were no indicators of this issue before it happened to my wife and I the first time on the highway. While I am grateful that nobody was injured, the situation could be completely different had the problem occurred just seconds later.