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What 6 owners told NHTSA about the 2021 Toyota Prius Plug-in Hybrid

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (6)Crash / fire / injury (1)Engine (2)Fuel system (2)Brakes (1)Driver assistance (1)Electrical system (1)Lane Departure (1)Speed control (1)Wheels (1)

Newest first · 6 complaints

Feb 23, 2026Fuel system

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

NHTSA ODI 11719876

Sep 18, 2024Speed control

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.

NHTSA ODI 11615271

Jul 14, 2023Driver assistanceLane Departure

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.

NHTSA ODI 11532235

Jun 13, 2023Electrical systemBrakesEngineCrash

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.

NHTSA ODI 11526893

May 11, 2021EngineFuel system

CARBON MONOXIDE SEEPS INTO THE PASSENGER CAR BUT DILLER CANNOT FIND IT AND DID NOT HAVE TOOLS TO DETECT CO LEVEL IN THE CAR. I CAN'T USE THIS CAR BECAUSE WAS POISONED MANY TIMES AND AFTER A SECOND CHECK-UP, THE LEVEL OF CO BECOMES HIGHER SO I CAN'T DRIVE THE CAR WITHOUT POISONING. PLEASE HELP ME. I AM WORRYING TO SELL MY CAR BECAUSE OTHER DRIVER WILL GET INJURY. THIS IS THE NEW CAR ONLY 7000 MILES.

NHTSA ODI 11416154

Mar 25, 2021Wheels

WHILE DRIVING ON THE I 4 WE HAD A BLOWOUT ON THE REAR PASSENGER TIRE. THE CAR HAD LESS THAN 200 MILES ON IT SO IT WAS BRAND NEW. THE DEALERSHIP FOUND OBJECT IN THE TIRE THAT COULD HAVE CAUSE THE PROBLEM THE ONLY CONCLUSION I COULD COME TO IS THAT THIS TIRE WAS DEFECTIVE. THE DEALERSHIP SAID I COULD HAVE RUN OVER A LARGE OBJECT OR A LARGE POTHOLE, WHICH I DOUBT.

NHTSA ODI 11404863

Working with the data? Download all 6 complaints as CSV · fetched from NHTSA July 14, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2021 Toyota Prius Plug-in Hybrid verdict →