Which parts fail
Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2009 Toyota Prius owners, lightly cleaned up (personal details are redacted by NHTSA).
The car stopped moving while I was driving. The engine is functional but it will not engage the drivetrain. The dashboard lights up intermittently. Most of the time the dash is dark. The local Toyota dealer will not take this car into the service department since it is over 10 years old and the dealer has not done all the regular servicings of the car. So I can not drive it.
This car cuts off power to save the powertrain from damage, that is what Toyota told me. You must be extremely careful when entering traffic because you can lose power for 2-3 seconds if the cars computer senses any wheel spin. The way I see it this is a machine that was designed by the engineers to save itself from damage, the safety of the driver is of no concern to the computer program. You must always!!! Be aware when driving this car that it can and will cut all power when you enter traffic. The best way to drive this car and stay alive is to make sure any approaching vehicles are much farther away than you would consider normal if you were driving any other car. Imagine in the future that a firefighting robot runs into a burning building to save you, the robot picks you up and starts to exit the building. …
Driving vehicle on a city street in drive gear and it slipped out of drive into neutral without warning. Tried to put it back in drive (as I was on the road) but every time I switched gears back to drive and released the gear shifter it would immediately pop back into neutral. I parked & turned the car off, waited and then turned it back on again. It seemed to be okay so I got on the freeway home and after I merged into traffic the same problem happened (but while I was driving at a much faster speed). I had to hold the gear shift down in drive the entire ride home (with my one year old in the car). I got home and after I parked and let the car sit I went back out and tried the car again and it happened again. I checked and the same problem happened in reverse (it won't stay in reverse, it just pops back into neutral).
Complete shutdown of Prius automobile with no warning while in motion on a city street. Rolled to a stop in safe area. Nothing worked except emergency blinkers. No instrumentation or warning lights appeared. The car was locked in FWD park and could not be towed by flatbed tow truck as there is no override. Lift tow truck was used to get to dealer. Diagnosed as melted hybrid invertor pump. Dealer replaced pump and fuse for a $641.47 cost to me. If this had happened on a highway/freeway it would have been a disaster. The complete loss of power without warning at freeway speed could very easily ended up as a multiple car pile up. Just the thought of crossing multiple lanes in traffic with no power, just rolling, makes me think it's time to get rid of this car.
Tl contact owns a 2009 Toyota Prius. The contact was driving approximately 2 MPH into a parking space with pressure applied to the brake pedal. The vehicle slowed down, followed by an unexpected acceleration. The vehicle crashed into a handicap parking pole. There were no injuries. There was a separate occasion when the gear selector failed to shift into reverse gear or park position. The failure occurred intermittently vehicle was taken to an authorized dealer. The technician stated that the vehicle was functioning properly. The vehicle has not been repaired at this time. The failure mileage was 36,000.
I own a 2009 Toyota Prius. I was pulling into a parking spot in a shopping center when my car suddenly accelerated. I hit a small tree and the car beside me. The car is being towed to camelback Toyota in phoenix az. The car seemed to accelerate even though I stepped on the brake. I did not step on the breake hard but the car just pulled ahead
Tl* the contact owns a 2009 Toyota Prius. The contact stated that the fuel gauge would provide inaccurate readings of fuel levels. While driving 20 MPH, the vehicle completely shut down without warning due to a bladder fuel tank problem. The vehicle was towed to the dealer who replaced the bladder fuel tank under warranty. The manufacturer was contacted who offered no assistance. The failure mileage was 43,000. The consumer stated Toyota paid for the repair. However, the gas gauge continues to be inaccurate and the consumer is unable to put no more than six gallons of gas in the vehicle. Also, at times, the vehicle would not shift into gear. Updated 06/30/11
Tl contact owns a 2009 Toyota Prius. While driving 2 MPH in reverse, the contact shifted the vehicle into drive and noticed that the vehicle was still reversing. The vehicle was then shifted back into reverse and then back into drive before the vehicle would drive forward. The failure has occurred on three different occasions the vehicle had not been diagnosed by the dealer. He contact also stated that when pressing the start button the vehicle would not start. The brake light also illuminates on the instrument panel even though the brakes are not engaged. The failure mileage was 5000 and the current mileage was 10000.
Loss of engine power in 2009 Toyota Prius. When accelerating into traffic in wet or low traction conditions every time one of the front wheels looses traction, the engine abruptly goes to idle for 3 seconds and the car severely decelerates. Only by removing your foot completely from the gas pedal and reapplying throttle will the car start going again. This extreme over-reaction of the traction control system is very dangerous in traffic. This over-reaction is most pronounced if turning to the right when a front wheel starts to slip. There should be a way to turn off the traction control system manually.
Service engine light, code p1121, coolant recovery tank flow control valve bad. There is a service campaign on this for 2007 Prius and the problem is supposed to be solve for 2009 Prius. Also this is part of the emission control system, as the purpose of coolant recovery tank is the warm up engine sooner to pass emission test. Called Toyota dealer, not covered by emission warranty. This is a known and very common problem and Toyota is dragging its leg on it.
Transmission complaints in other Prius years
Frequently asked questions
How common are transmission problems on the 2009 Toyota Prius?
NHTSA has 22 complaints about the transmission & drivetrain of the 2009 Toyota Prius, 4% of the model year's 502 complaints. The component named most often is automatic transmission (4 mentions).
Is there a recall for 2009 Toyota Prius transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2009 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 2009 Toyota Prius transmission problems start?
Half of the complaints with a recorded mileage happened before about 20,000 miles, and 58% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 0 fires and 0 injuries to transmission & drivetrain 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.