Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2006 Toyota Prius owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2006 Toyota Prius. The contact stated that while driving at an undisclosed speed, the vehicle lost power and immediately regained power. Approximately 24 hours later the check engine warning light illuminated. The vehicle was taken to an independent mechanic who diagnosed that the hybrid water pump was faulty and needed to be replaced. The vehicle was repaired. The local dealer was contacted and informed the contact that the vehicle was not included in the NHTSA campaign number 12V536000 (Engine and Engine Cooling, Hybrid Propulsion System). The contact indicated that the vehicle experienced the failure listed in the recall. The failure mileage was 167,000.
The contact owns a 2006 Toyota Prius. The contact stated while his wife was attempting to stop the engine and turn off the vehicle, the vehicle failed to turn off. There were no warning lights illuminated. The contact's wife was able to drive safely to the residence. The contact disconnected the battery and conducted a personal diagnostic test and the vehicle was operable. The vehicle was not diagnosed by an independent mechanic or dealer. The manufacturer was not notified of the failure. The approximate failure mileage was 265,817.
One afternoon, in the Summer of 23, I entered my Toyota Prius to run some errands. Once I proceeded to power on the car, none of the dashboard lights illuminated. This included the gas gauge, speedometer & transmission indicator. Fortunately, I was only driving a few blocks down the road from my residence as I live in a small rural town with little congestion, little traffic and mostly two-lane roads. I can't imagine this occurring in a much larger metropolitan city. When I arrived at my destination, I discovered that my Prius wouldn't shut off. This dashboard malfunction was preventing the Toyota from powering off. I quickly completed my errands with my vehicle running during this entire ordeal. Finally, when I returned home, I frantically researched on YouTube regarding this issue and discovered many others who also were having these no-illuminating-dashboard problems. …
Tl* the contact owned a 2006 Toyota Prius. While driving approximately 30 MPH, another vehicle suddenly stopped in front of the contact's vehicle. The contact depressed the brake pedal to the floorboard, but the vehicle failed to stop. The contact's vehicle crashed into a road sign. The air bags failed to deploy. The contact coasted to the side of the road and the engine failed. The contact was not injured and a police report was filed. The vehicle was towed to a dealer and an insurance lot. The vehicle was destroyed. The manufacturer was made aware of the failure. The approximate failure mileage was 196,000.
I am a rural mail carrier with well over 350,000 miles driven on my route without incident. I drive in all road conditions on gravel and paved roads. I was driving my 2006 Prius on a wet but not muddy gravel road at about 38 MPH. The back end began to slide a little. I let up on the gas with no response. I pressed the brake pedal with no response. I went into a deep ditch filled with 3 ft tall grass. I steered to drive the center of the ditch and continued with the brake fully depressed for about 15-20 ft, ripping the tall grass out by the root as I went. The car traveled over a driveway approach, still at 35 MPH, striking the approach with the left front corner with enough force to bend the frame and do other serious damage, but with no airbag deployment. I continued over the approach and down the ditch, still at 35 MPH, for another 30 or more feet. …
On the morning of May,04,2015 upon entering the car and starting it up the instrument panel fails to display. Not certain what the issue was I performed various check including the the accessory battery and attempted multiple times starting and stopping the car to no avail. I left the car where it was and a few hours later when I returned everything worked fine for a few more weeks then the issue occurred again. However, I have noticed that the issue is occurring now more frequently including when driving (stopped then go). Furthermore, whenever this issue occurs it becomes almost impossible to power the engine off and since their is no cluster display to let you know vital safety information, including speed, gas, mileage, gear (d-r-n) this creates an unsafe and hazardous condition for operators of this vehicle. Toyota motor corp. …
Tl* the contact owns a 2006 Toyota Prius. The contact stated that while driving at approximately 64 MPH, the vehicle stalled without warning. The vehicle was unable to restart. The vehicle was towed to hartford Toyota superstore located at (135 w service rd, hartford, ct 06120) where it was diagnosed that the battery and two ignition coils needed to be replaced. The vehicle was repaired however, the failure persisted while the check engine warning light and the ESP fault warning light illuminated. The vehicle was towed to lynch Toyota located at (179 tolland turnpike, manchester, ct 06042) where it was diagnosed that inverter water pump needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 237,000.
According to the Toyota dealership where I have my car maintained, my 2006 Prius is in need of a new motherboard. Apparently there was a recall on this prior to so many miles on the vehicle but I have missed this deadline as my car did not show these symptoms prior to the cutoff.. My Prius when turned on does not turn on the dash board features so I have no idea how fast I am driving. Once I reach my destination I am unable to turn my car off. The power button does not respond, usually for several hours. In these cases I usually leave my car on in the parking lot where I am and return over the next several hours to check on it. It tends to turn off after taking the car for a long drive several hours later. This occurs about twice a month now.
Tl* the contact owns a 2006 Toyota Prius. While operating the vehicle, the power steering suddenly malfunctioned and caused the steering wheel to become very difficult to turn. The vehicle was taken to the dealer where it was diagnosed that the power steering ECU was faulty and needed to be replaced. The vehicle was repaired. Also, while driving the vehicle, it suddenly stalled and would not restart. The vehicle was taken to the dealer where it was diagnosed that the throttle body was faulty. The failure was repaired. The contact also indicated that the air conditioner blower stopped operating and the front windshield could not be defrosted. The manufacturer was notified of the failures. The failure mileage was 200,500.
I was driving on a highway and the car on the right started to move to my lane without turning on turn signal, he probably didn't notice me as he was moving on me, I started to brake but brake pedal started to work at once, it started to work only after delay and after it started working I lost control over the car, ABS signal turned on and I started to move to the left. I tried to prevent it but car was totally out of control and this caused the accident. The same happened to my wife in February when she was driving my car on highway. She just couldn't stop even though the distance to the next car was long enough. Brake pedal started to work with the delay and she bumped into the next car.
Engine complaints in other Prius years
Frequently asked questions
How common are engine problems on the 2006 Toyota Prius?
NHTSA has 45 complaints about the engine & cooling of the 2006 Toyota Prius, 3% of the model year's 1,439 complaints. The component named most often is engine (4 mentions).
Is there a recall for 2006 Toyota Prius engine problems?
No. NHTSA lists no engine & cooling recall for the 2006 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 2006 Toyota Prius engine problems start?
Half of the complaints with a recorded mileage happened before about 107,000 miles, and 13% before 25,000 miles.
Is it dangerous?
Owners linked 4 crashes, 0 fires and 1 injury to engine & cooling 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.