Problems · NHTSA complaints

2021 Toyota Prius problems

Owners filed 6 complaints about the 2021 Toyota Prius with NHTSA between Mar 2021 and Feb 2026. The most-cited component is fuel/propulsion system (2).

Complaints
6
Filed with NHTSA
Crashes
1
Reported by owners
Fires
0
Reported by owners
Injuries
0
People reported injured
Deaths
0
Reported to NHTSA
01 —By component

Complaints by component

One complaint can cite several components
  1. Fuel/propulsion system2
  2. Engine2
  3. Vehicle speed control1
  4. Forward collision avoidance1
  5. Lane departure1
  6. Electrical system1
  7. Service brakes1
  8. Wheels1
  9. Other / unknown1

Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.

Data from NHTSA Complaints API · synced Nov 3, 2026NHTSA vehicle page
02 —Trend

When complaints were filed

Does it get worse with age? Complaints per calendar year filed
View as table
Model yearComplaints filed per calendar year
20212
20220
20232
20241
20250
20261

Mileage at failure isn’t a structured field in NHTSA complaint data, so we don’t chart it. Some owners mention it in their reports below.

03 —Owner reports

Top problems in owners’ words

Verbatim from NHTSA complaints, newest first

Fuel/propulsion system

2 reports
“When i am going down it's charging when the charge reaches 6 from 8 the engine starts working and stop changing at that point and the power continues comes from engine only without the hybrid battery and there are no codes”
Owner complaint to NHTSAFiled Feb 23, 2026Fuel/propulsion systemODI 11719876

Engine

2 reports1 crash
“The car accelerated without my foot on the accelerator, brake did not respond, and I had to drive through grass and a rock-filled ditch until after about 10 seconds the car returned to my control.”
Owner complaint to NHTSAFiled Jun 13, 2023Electrical system, Service brakes, EngineCrash reportedODI 11526893

Vehicle speed control

1 report
“The contact owns a 2021 Toyota Prius. The contact stated while driving approximately 35 - 45 MPH, the vehicle independently accelerated. The brake pedal was depressed but failed to stop the vehicle immediately. The contact swerved around the vehicle in front and ended up on the opposite side of the roadway. The contact attempted to avoid oncoming traffic and swerving around all the other vehicles and ended up in a ravine. The contact's husband depressed the START/STOP button from the passenger’s side to turn off the vehicle, enabling the vehicle to come to a stop. The contact restarted the vehicle and continued to drive the vehicle to the dealer at slow speeds. The dealer was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was made aware of the failure by the dealer. The failure mileage was 56,000.”
Owner complaint to NHTSAFiled Sep 18, 2024Vehicle speed controlODI 11615271

Forward collision avoidance

1 report
“The Lane keeping assist used in radar cruise control mode during some drive cycles will attempt to maintain the vehicle position to the far extreme of the lane and in some cases actively veer out of the lane. My safety ant others can be put at risk when the vehicle behaves outside of its design parameters like this. To solve the issue the vehicle must be pulled over, turned off, then restarted. After the restart it will resume functioning normally, maintaining lane positioning as intended within the limits of the system. The trigger for this is unknown but could be speculated that it is drive cycle dependent and may start during initialization. The problem has not been reproduced by a dealer or service center due to its intermittent nature. There are no warning indicators or lamps on when this occurs.”
Owner complaint to NHTSAFiled Jul 14, 2023Forward collision avoidance, Lane departureODI 11532235

Lane departure

1 report

Electrical system

1 report1 crash
Data from NHTSA Complaints API (owner reports, unverified) · synced Nov 3, 2026

Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.