Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2011 Toyota Prius owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2011 Toyota Prius. The contact stated while her husband was driving approximately 40-50 MPH and depressing the accelerator pedal, the accelerator pedal failed to go back to the normal position and remained stuck. There was no warning light illuminated. The contact's husband depressed the brake pedal, and the engine revved significantly. The driver was able to pull to the side of the road. The driver turned off and restarted the vehicle, and the vehicle responded as needed. The dealer was notified of the failure and referred the contact to the manufacturer for assistance. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 119,000.
The conditions listed in Toyota Customer Support Program ZJB for the brake booster and master cylinder occurred after the 10 year in service date on my vehicle. Brake, ABS, and Traction control warning lights turn on intermittently and when this happens brake response is poor and cruise control shuts off. When applying the brakes an audible tat tat tat sound can be heard from the front of the car that sounds like the ABS being triggered. You should have toyota recall impacted cars and fix the issue as outlined in the TSB and support campaign.
I was driving my car and suddenly the traction , hand brake and ABS sign started showing up. I usually apply only 10% of force on brake pedal but after this I have to apply almost 60% of force to even slow down the car. Almost 90% force to stop the car It has threatened safety of my family. When diagnosed at autozone they told cannot determine error code. When reading in internet this seems to be common problem in prius. Please help is fixing the issue as it is not at my fault. This seems to be manufacturing defect.
I was driving the vehicle around 55 mph when a check hybrid system warning popped up. About 30 seconds later the vehicle went from being in drive to B (brake mode) and the vehicle began to slow at a rapid pace with no warning. Could potentially cause an accident as this occurred with very little warning.
Tl* the contact owns a 2011 Toyota Prius. While attempting to park, the driver depressed the brake pedal and suddenly the vehicle accelerated forward and crashed into a pole. During the crash, the front end sustained significant damage. The air bags did not deploy. No injuries were reported and a police report was filed. The vehicle was destroyed. The manufacturer was not notified of the failure. The failure mileage was 21,000.
Making right turn into a parking spot and the car accelerated striking a parked car to my right and my car was stopped by a cement handicap ramp. There was extensive front end damage to my car, as well as the front passenger door. The car on my had the right front bumper removed and the wrought iron railing on the ramp severely dented.
Every once in a while - it can be months between events - our Prius momentarily slams on the brakes when driving at highway speeds while nothing else is going on. We know it's not operator error. It's happened to my wife several times and me once. When it happened to me I was driving straight ahead on a dry, lightly traveled divided highway during the day. Everything on the dashboard lights up, alarms go off, the car decelerates like I suddenly stomped on the brake pedal though my foot never moved off of the gas, it lasts for maybe a second and then the car is back to normal. It's the same each time it's happened. Luckily each time this has happened we haven't had anyone tailgating us. We've taken it to the dealer multiple times. The first couple of times they looked at us like we were loony. …
Brake light, ABS,slip indicator,brake system warnig light system all came on while driving at high velocity [75m/h] in the rain and lost 75% of the braking power plus the car started to slide. Needless to say this was a catastrophic failure of the entire brake system on a car that has a customer support program notification from Toyota[zjb] that was sent to me with a warning of such occurrence. This is down right irresponsible to a major car manufacturer to allow these vehicles on the road without testing the entire system on each of these affected vehicles and with for a catastrophic failure to occur and cause public harm or even death. I had just taken the vehicle for service a few weeks prior where I explained the service advisor of an issue with brake pulsation. …
In motion while accelerating past a slower car. Heard and felt a pronounced thump and lost engine power on busy local thoroughfare. Moved to a turn lane and stopped. Multiple dashboard lights and "check hybrid system" on LED display. Power off car, and back on twice and got the same error on display. Found that car could move on EV power and I got it into a safer location at an adjacent parking lot. Had vehicle towed to repair facility. As a driver this was disconcerting as I could not clearly determine if the car was at all driveable. If a driver were to stop immediately in the same situation they would be on the roadway. If I had not pressed on the accelerator pedal after powering on the car again I would not have known I could move the car to a safer location. …
Break actuator is failing in my 2011 Toyota Prius. The car now has a unpredictable ABS breaking system. Sometimes the breaks work and sometimes they quickly fail and a error light comes on. The light than goes out as if nothing happened and all is fine. This is a very dangerous problem that will lead to many accidents because the vehicle tells you its good to go, mean while the ABS system is failing to stop the vehicle intermittently. I am scared because I dont know if the car will do this on a turn then lose control injuring myself and others.
Acceleration complaints in other Prius years
Frequently asked questions
How common are acceleration problems on the 2011 Toyota Prius?
NHTSA has 28 complaints about the speed control & acceleration of the 2011 Toyota Prius, 5% of the model year's 521 complaints. The component named most often is accelerator pedal (1 mentions).
Is there a recall for 2011 Toyota Prius acceleration problems?
No. NHTSA lists no speed control & acceleration recall for the 2011 Toyota Prius, though it has 6 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2011 Toyota Prius acceleration problems start?
Half of the complaints with a recorded mileage happened before about 21,000 miles, and 52% before 25,000 miles.
Is it dangerous?
Owners linked 3 crashes, 0 fires and 0 injuries to speed control & acceleration problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.