2015 Toyota Prius · symptom sheet
Brake pedal goes hard or the booster or vacuum pump fails
- 54owner reports
- 119,000median miles
- $3,000median quote
- 1involved a crash
Newest report Sep 17, 2026 · checked Sep 29, 2026
54 of the 92 reports of brake wear on the 2015 Prius describe brake booster failure.
Part of Brakes grind, pulse or wear early (92 reports) · also: ABS light on, brake light on
Tick what matches of 54 reports
Brake booster failure on other Prius years
Report counts are for each model year on its own, so a newer car has had less time to collect them. Model years with too few reports of it for a sheet: 2016.
What this problem usually is
This is the narrower sheet inside brakes for reports about a hard pedal or a failed power assist. The pedal stops feeling normal: it turns stiff, takes far more force, and the car needs a longer distance to stop.
What got replaced
Owners who name the part that was replaced mention the brake booster (53 reports) and the master cylinder (11 reports).
Recalls and investigations
No recall on the brakes covers the 2015 model year as of Sep 29, 2026.
NHTSA investigations into the brakes on the Prius
Brake actuator valve wear. Open.
Brake actuator valve wear. Closed jan 21, 2021.
Braking performance, hybrid vehicle. Closed jul 12, 2010.
What owners paid
18 of the 54 reports quote a price. Each dot is one quote. The middle half runs $3,000 to $3,631.
When it happens
The middle half of failures fell between 87,000 and 150,000 miles, from the 25 reports that gave a mileage.
Is this a known problem?
The manufacturer has sent NHTSA 2 service bulletins or notices for the 2015 Toyota Prius that deal with this problem. Newest first.
Federal rules make a manufacturer send NHTSA a copy of any notice about a defect that goes to more than one dealer or owner. Most of these are service bulletins, the repair instructions manufacturers send to dealers. NHTSA generally leaves safety recall bulletins out of this file, and recalls are listed separately.
Dealer Package: Toyota has received reports about certain internal malfunctions of the brake booster assemblies in some of the subject vehicles.
Dealer Letter: March 7, 2019 ZJB Phase 2 Launch for Certain 2011 ? 2015 Model Year Prius Vehicles and Certain 2012 ? 2015 Model Year Prius PHV vehicles.
What owners wrote
“The brake booster suddenly fails at 54k mile. Brake responds slower and need to push the brake pedal all the way It seems a lot of 2010-2015 Prius are facing this problem ABS light, skid light, and brake light was on when it happened, first appeared on Feb 6, 2026 Have to replace brake boost for ~$1500”
Filed Feb 9, 2026
“Defected brake booster hard brake suddenly car less than 100 000 miles many vehicles with the problem”
Filed Jan 16, 2026
“Code C1391 Leakage in Accumulator abnormal. This required replacement of the master cylinder, brake booster pump assembly. This fault resulted in mushy brake pedal and loss of abs system. The components were replaced at a Toyota dealership. Total cost was $3207.82. Apparently this was a known issue with Toyota for Prius models 2010 through 2015.”
Filed Aug 22, 2025
“Failure of the: pump break booster actuator Had it towed to Toyota and they said itâs a $3,500 repair”
Filed Aug 11, 2025
Should you keep driving it?
This page can't tell you that. 1 of 54 reports involved a crash and 1 people were hurt. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.
File your own report with NHTSA. Complaint counts are how a problem gets an investigation. How reports land on this sheet.
Guide Taking it to a shop? How to describe this problem so it gets found