About this problem
On hybrids, braking is shared between the electric motor, which recovers energy, and the normal friction brakes. A brake actuator, a pump and valve unit, blends the two and controls the pressure at each wheel. When the actuator or its accumulator fails, owners report warning lights, a pump that buzzes constantly, and brakes that feel different or briefly weaker, especially over bumps or at low speed.
Across all owner complaints filed about the Toyota Prius since 2012, 486 (29%) describe brake actuator and braking problems, making it the most reported problem we track on the Prius. The reports cluster on the 2012, 2013 and 2014 model years, and the 2013 drew the most, with 186. It tends to show up at higher mileage: half of the owners who gave a mileage were between 35,000 and 139,000 miles. 26 reports describe a crash or fire linked to it. One recall is related to it, and recall repairs are free at any dealer.
What owners report
Owners of the 2012 to 2014 Prius report the brake pedal sinking, the brakes feeling weak for a moment, and warning lights for the brake system. Many cases are traced to the brake booster and actuator assembly, which tends to fail at high mileage, often past 100,000 miles.
How it gets fixed
The fix is replacing the brake booster pump or actuator assembly. Toyota extended coverage on this part for some years, so ask a dealer to check the VIN.
Typical cost: Replacing the brake actuator assembly typically costs $1,500 to $3,000 if not covered.
Complaints by model year
In owners' words
"The car brakes failed at low speeds (10-15 mph) and bumped into the car in front in a stop-and-go traffic on the wet freeway after a recent rain."
2014 Toyota Prius, 176,619 miles
"Brake accumulator failure resulting in not being able to stop properly. Brakes began pulsating and making sounds under passenger seat. Electric pumping sound became more and more prominent over time."
2013 Toyota Prius, 108,000 miles
"Car was in motion and brake pedal went half way to floor and abs, brake, traction control and tire sensor lights came on. Master cylinder or brake booster seem to have failed."
2012 Toyota Prius, 212,566 miles
Excerpts from public owner complaints filed with the National Highway Traffic Safety Administration, lightly trimmed.
Related recalls
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2019 Lexus LS500, LC500, ES300h, UX250h, LS500h, Toyota Prius, RAV4 HV, 2019-2020 Toyota Prius Prime, and 2020 Corolla HV vehicles.
Recall repairs are free at any dealer. Check a specific car by VIN at nhtsa.gov/recalls.
Service bulletins
Toyota has sent dealers 2 bulletins that mention this problem on the Prius. A bulletin tells technicians how to fix a known fault. It is not a recall, so the repair is usually free only while the car is under warranty or covered by an extension.
Dealer Letter: March 7, 2019 ZJB Phase 2 Launch for Certain 2011 ?
Dealer Package: Toyota has received reports about certain internal malfunctions of the brake booster assemblies in some of the subject vehicles.
Government investigations
Defect petition DP19004 · 2012–2015 · opened Sep 2019, closed Jan 2021
Defect petition DP23005 · 2012–2015 · opened Nov 2023
Before you buy a Prius
- Listen for the brake pump running loudly or often after you switch the car on.
- Make sure no brake warning lights come on during the test drive.
- Ask whether the brake actuator has been replaced.
Questions
Which Toyota Prius years have brake actuator and braking problems?
Complaints are highest for the 2012, 2013, 2014 model years. The 2013 drew the most, with 186 reports.
At what mileage does it usually start?
Among owners who gave a mileage, the middle figure was about 100,000 miles, and half reported it between 35,000 and 139,000 miles.
How much does it cost to fix?
Replacing the brake actuator assembly typically costs $1,500 to $3,000 if not covered.