really awful
Crashes / Fires:
4 / 0
Injuries / Deaths:
1 / 0
Average Mileage:
61,174 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2001 Toyota Prius engine problems

engine problem

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2001 Toyota Prius Owner Comments

problem #16

Jun 192015

Prius 4-cyl

  • 159,700 miles


The car suddenly lost power without any warning while driving 65+ mph on the freeway. The check hybrid warning light came on. The car became dangerously unresponsive, luckily we were near an exit and were able to coast to safety. The hybrid system was expecting information from the accelerator, and when it doesn't receive it, either the gas engine, or the electric engine, or both engines fail to operate. Toyota has service bulletin 2001 Toyota Prius unknown or other service bulletin 117006 action number: 635861 service bulletin number: 117006... report date: Sep 12, 2002 component: Unknown or other.... summary: Some vehicles may exhibit a master, hybrid and malfunction indicator warning light on with diagnostic trouble code P1120.,,, P1120 Toyota description accelerator pedal position sensor is mounted on the throttle body and it has the 2 sensors to detects the accelerator position and a malfunction of the accelerator position. The accelerator pedal position sensor is connected with the accelerator pedal by the accelerator wire. The ECM judges the current opening angle of the accelerator pedal from these sensor signal inputs and it controls the throttle motor based on these signals. If the the P1120 code is stored, the ECM shuts down the power for the throttle motor and the magnetic clutch, and the throttle valve is fully closed by the return spring. However, the opening angle of the throttle valve can be controlled by the accelerator pedal through the throttle cable. I have since learned that the accelerator sensor assembly is probably at fault, which is a high cost item $300 dollars or more which Toyota would balk at replacing in a recall. This happened once before, but I don't recall the date.....updated 08/24/15

- San Jose, CA, USA

problem #15

Mar 152010


  • 120,000 miles
Car rapidly accelerated without my foot on the gas pedal and did not slow down until my foot hit the brake. Brought the vehicle to mcgee Toyota and they replaced the gas pedal. It was a $600.+ repair. Within the year the news reported abnormal acceleration with the Prius line and I quickly contacted Toyota management. They denied my claim saying that these incidences were as a result of floor mats? I reported it to [xxx](MA) representative for consumer protection and have not received a response (this was over two years ago). I recently heard about your Agency and decided to file a report. Information redacted pursuant to the Freedom Of Information Act (FOIA), 5 U.S.C. 552(B)(6).

- Scituate, MA, USA

problem #14

Sep 012009


  • 70,000 miles
On two occasions, I experienced unintended acceleration in my 2001 Toyota Prius. The first time it happened, it happened I thought I might have pressed the accelerator by mistake. I had to slam on the brakes to stop the car. I didn't believe anyone would believe my story because of the Audi 5000 incidents. Then it happened again. Then Toyota began its recalls.

- Hurdle Mills, NC, USA

problem #13

Feb 102010


  • 172,000 miles


Driving my 2001 Prius down rt 95 in ct. Suddenly lost power. I was able to drive - electric drive only, no gas power. I made to the exit in wesport and found a Toyota dealership open. The diagnosis, via codes, was failed accelerator pedal. Resetting the computer and restarting the car a few times allowed it to work enough for me to get home. I have still not repaired the accelerator. Lately this problem happens nearly every time I start the car...the engine stalls immediately or loses power down the road. Restarting 2 or 3 times "fixes" the problem most of the time. My research has shown that this problem is common, and called "big hand syndrome" among 1st generation Prius owners, and accelerator pedal repair is the common fix. I believe the 2001-2003 Prius should be included in the Toyota accelerator pedal recall.

- Lexington, MA, USA

problem #12

Apr 152008


  • 137,700 miles
While driving along on interstate, got warning triangle and low main battery information. Immediately, car began to speed-up on its own. I applied very hard braking to try and slow down while trying to move to the right lane with traffic on my right. Car did not slow down but I managed to avoid traffic and get onto the right lane, where there was an exit from the interstate. I made the exit and was able to get control of the acceleration. I then drove the rough running car to the my dealer off that exit. They replaced the main battery, and everything is now fine. I feel that I was very lucky that nobody got hurt!

- Tyrone, GA, USA

problem #11

Jan 102010


  • miles
I saw that the Japanese government is making Toyota look into the following complaint in newer model priuses. "the vehicle surged forward or temporarily lost braking after driving over a pothole or other uneven surface. This is a reoccuring problem." My 2001 Prius has this problem all the time. In addition the car had the hybrid batteries catch on fire, the catalytic converter fail, the ECU for the brakes fail, the power steering fail, the brake pump leak, the computer fail (which caused the car to improperly shift gears). These issues were all fixed for free by Toyota except the ECU for the brakes and the brake pump which were fixed, but at my expense. No injuries occured.

- Austin, TX, USA

problem #10

Sep 092006


  • 42,000 miles


The contact owns a 2001 Toyota Prius. While driving between 65-70 mph, the vehicle did not respond when the accelerator pedal was depressed. All of the instrument panel indicators illuminated and the engine suddenly stalled. The vehicle coasted to the side of the road and the engine failed to restart. While the gear shifter was placed in park, the vehicle accelerated unexpectedly and crashed into a guardrail. The driver sustained a whiplash and a police report was filed. The vehicle sustained severe damage and was towed to an authorized dealer. The vehicle was repaired for body structure damages. The technician performed diagnostic tests, but was unable to duplicate the failures. The vehicle was taken back to the authorized dealer on five separate occasions for identical failures, but there were no resolutions. The failure mileage was 42,000 and current mileage was 68,000.

- Honey Brook , PA, USA

problem #9

Oct 082005

Prius 4-cyl

  • Automatic transmission
  • 60,500 miles
2001 Toyota Prius: Accelerator sensor failure for several weeks leading up to the failure, there was a slight (but definite) sensation of deceleration when trying to maintain steady speed. At the time of failure, the vehicle hesitated/stalled and the "master warning light" came on. Local dealer (355 Toyota, rockville, md) replaced the part at a cost of $700. Should a part this expensive (and so critical to vehicle function) be failing at 4 years?

- Gaithersburg, MD, USA

problem #8

Jul 252005

Prius 4-cyl

  • Automatic transmission
  • 74,000 miles
Vehicle stalled/died, and lost power while driving 5 mph. Throttle body module failed. There was a NHTSA recall but this involved a chemical in the pruis car battery. L. yes. Car has broke down several times since. The stalling is still a problem.

- Atlanta, GA, USA

problem #7

May 132005


  • Automatic transmission
  • miles
Going at highway speed, car suddenly lost power, slowed down to a max. Speed of 37 mph, running mostly on electrical power. Master warning light (triangle with excalmation point) lit up. Gas engine would periodically start up, but was not responding to accellerator pedal. After pulling over and shutting down vehicle, I was able to restart and continue normally.

- Wyomissing Hills, PA, USA

problem #6

Nov 152003


  • Automatic transmission
  • 37,700 miles


Problems started in November 2003. Had oil changed and an hour later all the warning lights came on in the vehicle. Immediately returned to the dealership where it took 2 weeks to replace the fuel pump (37,000 miles). Since then the car has been back to the dealership an additional 9 times to the current date (May 2005) for several different things. The computer has been replaced two times. The engine has been replaced. The injectors cleaned, then a few months later had to be completely replaced. The throttle body has been replaced. I have been driving the car when it would not acelerate and had to pull over in traffic. The first time the dealership said there were no warning lights when the car got to the dealership and they could not recreate the codes or situation so they could not do anything. The second time (April 2005) all four injectors were replaced as well as the mass air flow system. The car has been in the service department at our Toyota dealership for a total of 17 times since the car arrived at approximately 180 days!!! 10 of those 17 times has been because the warning lights have come on. Have entered into arbitration and we are awaiting an answer on the decision.

- Spartanburg, SC, USA

problem #5

Mar 102004

Prius 4-cyl

  • Automatic transmission
  • 45,000 miles
2001 Toyota Prius-sudden drop in speed-could not exceed 17 mph. Dangerous in traffic Toyota replaced computer-old parts not available incident date is approximate-took 2 1/2 months to repair

- Fountain Valley, CA, USA

problem #4

Jul 212003


  • miles
A reader of the san diego union-trib wheels section responded to an article regarding unexpected acceleration from electronic throttles and the editor forwarded the letter to NHTSA.** answer required***. while parking in a diagonal parking space the consumer's vehicle accelerated suddenly across a sidewalk and hit an electric box. This sudden acceleration problem happened again while the consumer was parking. That time not accident occurred.

- San Diego, CA, USA

problem #3

Sep 102003

Prius 4-cyl

  • Automatic transmission
  • 60,189 miles
I own a 2001 Toyota Prius. Several times in the last few months I have experienced a loss of power combined with my dash warning lights. I had one similar incident last year. The dealership claims their diagnostics find no problem (no codes = no problem). Therefore nothing is resolved and the car remains prone to loss of power, a dangerous condition when traveling on any freeway. By looking at the chat boards (yahoo in particular) it's evedint ai am not an isolated case. I believe Toyota has an obligation to address and correct this issue. Thank you for your time. Richard torok

- Hermosa Beach, CA, USA

problem #2

Jan 012002


  • miles
The consumer states that the vehicle had gone out of control. The consumer was coasting into the driveway, when she placed her foot on the brake, the vehicle surged into the garage and damaged items. The consumer no longer wants the vehicle because she feels unsafe. The consumer said that Toyota didn't want to except responsibilty, even though the service manager did report that the gas engine surge could occur in order to charge the battery.

- Clearwater, FL, USA

problem #1

Aug 122001


  • miles
At 45mph on dry pavement, clear weather conditions I disengaged cruise control by tapping brakes. So that I could accelerate into traffic. The vehicle pulled hard to the left. I then found myself in a counterclockwise skid across the pavement as I left the pavement I felt the rear of the vehicle drop. Now spinning I bounced off a tree and into a drainage ditch with about 1 and 1/2 foot of mud and water. It was then I noticed that one of the wheels (left rear) had separated from the vehicle and was on the other side of the ditch. It all happened so fast I have no idea of the actual cause. The studs which hold the wheel to the axel shearedoff, ans axle snapped, the undercarrage and supports were tangled. Fhp officer at site indicated it could have been mechanical malfunction of some sort. Because of conditions I contacted Toyota as well as insurance co (progressive). No one has yet evaluated the cause. Toyotas first comment was "what do you expect from an investigation" my answerwas " to prevent a similar event in the future". as I related the event to every one I also noted that the steering didnot let me correct the skid. The vehicle is currently held in limbo by insurance and Toyota. While I am walking. All safety equipment functioned properly.

- St Augustine, FL, USA

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