2019 Toyota Prius Driver assistance Problems

Since October 2023, my 2019 Toyota Prius has developed severe and unpredictable driving behavior after a regular brake service, which may have triggered or coincided with a software or ECU update. The car, which had been driving smoothly since I bought it in 2021, suddenly began showing false braking, steering interference, and lane instability — as if the car were trying to “correct” problems that didn’t exist. These interventions often happen on highways or during turns, creating serious safety risks for both driver and passengers. I’ve spent months and thousands of dollars replacing parts, performing alignments, and recalibrating sensors, including at Toyota dealerships. The problem persists because it is software-based, not mechanical. I discovered that in mid–2023, the NHTSA announced upcoming rules requiring Automatic Emergency Braking (AEB) with pedestrian detection by 2029. Around that same time, reports from multiple drivers (Toyota, Honda, Hyundai, Ford, Subaru) began to appear describing the exact same issues. It seems manufacturers began silently updating vehicles to meet anticipated compliance standards. However, this introduced overly sensitive and malfunctioning driver-assist systems. The most alarming part is that the driver cannot fully disable these features — the “off” button only reduces their intervention. This means when the system malfunctions, the driver is forced to operate an unsafe vehicle. As a professional rideshare driver, this problem destroyed my ability to work. Passengers reported me for unsafe driving because of the car’s erratic behavior. I eventually lost my vehicle and income. I believe this is a systemic safety defect linked to premature or unregulated implementation of AEB software. Drivers deserve the right to fully disable malfunctioning systems that endanger lives. This is not just a car issue — it’s a public safety crisis that must be urgently investigated.

NHTSA ID

11692652

Incident

Oct 1, 2023

* I was pulling into a parking space at a slow speed. When I applied the brake the car accelerated causing the car to scrape the car next to the space. The car then stopped. * The acceleration was out of my control and the brakes did not stop it. Fortunately there was no person in front of me. * The Tow truck operator who came to get the car experienced the same issue when pulling into the bay at the dealer. I do not know about the manufacturer during their inspection as they did not provide me with that information. * Toyota had an inspection performed and that report was submitted to Toyota on August 20. We just received notification from Toyota that they found no problem with the car. * No warning lights noted.

NHTSA ID

11620209

Incident

Jul 31, 2024

I was idling at a parking space and went to turn off my car. The vehicle surged forward and the BRAKE sign came on. I pushed my brake to the floor and nothing happened. I was moving toward a brick wall so I put in in reverse and the car surged backwards. The BRAKE sign came on and I pushed the brake to the floor and again nothing happened and I ended up hitting the car behind me. I immediately took my car to the dealership where they kept it for 3 days and said they could find nothing wrong and it was safe to drive. I just got it back from having the body work done and am afraid to drive it as this might happen again or worse. I am reporting it to let you know and to see if this has occurred and been reported as happening in this make and model previously. I also have 2 witnesses to what happened.

NHTSA ID

11585051

Incident

Apr 8, 2024

The contact owns a 2019 Toyota Prius. The contact stated while at a complete stop, another vehicle crashed into the rear of the vehicle and the vehicle began to accelerate unintendedly. The air bags failed to deploy. The brake pedal was depressed but failed to respond. The contact stated that he was able to prevent a crash by avoiding several vehicles while continuously depressing the brake pedal. The brake pedal responded; however, there was 62-100 ft. stopping distance delay. The contact veered to the side of the road for a moment. The contact stated that as he restarted the vehicle, the vehicle operated as needed. There was no warning light illuminated. There was no police report filed. There was no injury sustained. The contact was able to drive to his workplace. The dealer and the manufacturer were not notified of the failure. The vehicle was not diagnosed or repaired. The failure mileage was approximately 78,000.

NHTSA ID

11504545

Incident

Jan 24, 2023

Mileage

78,000 mi

Whenever it rains the warning message clean parking assist sensor comes on while you are driving. Even after you clean the sensors the warning continues to beep contiously. You can press the back button but it will not stop. Also proximity sensor comes on with this incident. After the rain stops the problem stops.

NHTSA ID

11468535

Incident

Jun 8, 2022

VEHICLE INVOLVED IN A ACCIDENT. VEHICLE BRAKE SYSTEM DID NOT WORK. DRIVER HAD FOOT ON BRAKE PEDAL. ANTI COLLISION BREAK SYSTEM DID NOT WORK, VEHICLE SLID FOR 20FT INTO A STOPPED FOR. 2019 PRIUS WAS GOING 35 MPH BEFORE RISK OF COLLISION WAS REALIZED. SIGNIFICANT DAMAGE DONE ON PASSENGER SIDE BUMPER. NO AIR BAGS DEPLOYED.

NHTSA ID

11390410

Incident

Dec 3, 2020

Mileage

16,443 mi

PRIUS STALLS IN THE RAIN DESPITE NOT BEING A RECALLED MODEL. PCS SENSOR IS AFTERMARKET, PEDESTRIAN WARNING ALERT NOISE IS OFFLINE, SUSPENSION IS CRACKED, ENGINE MAKES CREAKING NOISE AT LOW SPEED TURNING. I WORKED FOR TOYOTA AS A SALESPERSON AND THEY REALLY TOOK ADVANTAGE OF ME. *TR

NHTSA ID

11327502

Incident

Jan 16, 2020

Mileage

52 mi

I WAS TURNING TO EXIT A FREEWAY AND ALL OF A SUDDEN MY CAR CAME TO A STOP (ABOUT 55MPH TO 0) IN A MATTER OF SECONDS WITH NO WARNING. IT THEN TOOK A FEW SECONDS BEFORE I WAS ABLE TO GET THE GAS TO WORK AGAIN. NO CARS WERE AROUND ME LUCKILY.

NHTSA ID

11268309

Incident

Oct 13, 2019

Mileage

1,495 mi

BOUGHT A NEW 2019 PRIUS FROM GROSSINGER TOYOTA ON 9/13, WENT BACK TO THE DEALER ON 9/16 TO GET MY OLD CITY STICKER FROM MY OLD CAR (THIS NEW CAR ONLY HAD 61 MILES), THE NEW CAR BROKE WHILE I WAS THERE. THE ENTIRE DASHBOARD WENT OFF (BLINDERS CANNOT BE TURN ON. NO INDICATION OF SPEED, NO INDICATION OF VEHICLE LEVEL, ETC). ANYTHING THAT'S ON THE DASHBOARD WENT BLANK. I TURNED ON AND OFF THE NEW CARD A FEW TIME, BUT THE RESULT WAS THE SAME. TOYOTA TECHNICIAN COULDN'T FIGURE OUT WHAT WENT WRONG THEMSELVES. WHEN THAT HAPPENED, I WAS JUST ABOUT READY TO LEAVE THE DEALER, THEN I QUICKLY WENT BACK TO SHOW THE GROSSINGER DEALER.

NHTSA ID

11257336

Incident

Sep 16, 2019

Mileage

61 mi