Huge win for car owners! All TSBs to be made public. The Center for Auto Safety just made the NHTSA (US Government) make public the full text of all TSBs from now on. They are the same organization that has petitioned the NHTSA & filed lawsuits to protect car owners over exploding gas tanks & other major safety issues. Whenever you drive in your car, you are safer thanks in part to a lot of work over the years by this small but very effective consumer advocacy group.

Please take a moment & say thank you by donating $5 or whatever you can to the Center for Auto Safety.


definitely annoying
Crashes / Fires:
0 / 0
Injuries / Deaths:
0 / 0
Average Mileage:
24,024 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.

2004 Toyota Prius engine problems

engine problem

Find something helpful? Spread the word.
Get notified about new defects, investigations, recalls & lawsuits for the 2004 Toyota Prius:

Unsubscribe any time. We don't sell/share your email.

2004 Toyota Prius Owner Comments (Page 1 of 3)

problem #45

Mar 052011

Prius 4-cyl

  • 123,000 miles


I was driving on the freeway at about 63 miles per hour, I had been driving for about 20 minutes when my engine cut out, all the lights on my dash turned on including the check engine and red triangle warning light. I drifted to the shoulder and powered the car off. I tried to start it 2 more times, both times the engine did not start and the red triangle and the check engine lights came on again. I waited longer and tried to power up the engine again, it started with the check engine light on. I took it to the dealership 3 days later (they could not see me sooner), ran the codes and it only came up with the code poaof, which means that the engine did not start. They had no explanation of what happened and did not seem to share my concern that this could happen again. The did recall work for me and sent me home.

- Los Angeles, CA, USA

problem #44

Feb 012010


  • 61,000 miles
The contact owns a 2004 Toyota Prius hybrid. While driving approximately 60 mph, the check engine warning light, and an unknown warning light illuminated on the instrument panel. The dealer was notified and advised the vehicle was safe to drive; unless the temperature, brake or oil warning lights illuminated. The vehicle began to lose power and the anti-lock brake system warning light illuminated. The vehicle was maneuvered to the side of the highway. The vehicle was towed to the dealer. The failures were related to the inverter water pump and the skid control electronic control unit (ECU). The inverter water pump was replaced. The failure occurred a second time. The vehicle was repaired for the malfunction. The failure and current mileages were 61,000.

- Mesquite, TX, USA

problem #43

Feb 182010


  • 122,271 miles
We own a 2004 Toyota Prius. On 02/18/2010 it lost power on the road, major malfunction lights came on, among others, and had to be towed to the Toyota dealer in carlsbad, ca. After diagnosing the problem, they said the computer had failed and needed to be replaced. When the computer was replaced it started transmitting new problem codes, namely, poa94, poa78, PO279, and PO555, which meant that the transaxle had failed, and computer codes show that the inverter could fail also. Total repair cost: $5,594 so far. If the inverter fails, it would be a total of $9,843 to repair. I don't see who would pay this exorbitant amount, let alone being able to afford it. The same incident occurred on 09/15/2008. The Prius had lost power and we took it in to the dealer. They performed a diagnostics test, test drove the vehicle on the freeway for 9 miles, it ran O.K. and no computer trouble codes were found at the time. This sounds like it was a Prelude to the vehicle failure were are experiencing today, and we are suspecting it has to do with the electronic system. As it stands now, the Prius is sitting at the Toyota dealer. They had removed the new computer in light of the fact that the entire vehicle is totaled. In short, the Prius was fine one day and totaled the next. They told me that this doesn't happen very often. Please let us know what we can do to resolve this problem. Thank you.

- Carlsbad, CA, USA

problem #42

Jan 232010


  • 87,000 miles


On 23 Jan 2010, while driving I-85N in the South Carolina mountains the car stalled at 70mph. An audible alert sounded, the car jerked and three warning lights went off. I coasted the car to the shoulder and shut the car down. I restarted the car -- the warning lights cleared -- and continued driving. About 30 minutes later, still in the mountains, the same things occurred (stall while driving 70mph on the interstate.) when I restarted the car a yellow "!" warning remained on. I continued the trip to Virginia with no further problems. The warning light went out. On 5 Feb 2010, while driving on I-95S in the South Carolina mountains the car stalled, warning lights and audible alarm sounded. Upon restart the "!" stayed on. This happened two more times; once on I-95 and once on I-20. The last two times the red triangle warning light stayed on also. On 6 Feb 2010, I took the car to Toyota center in columbia SC. The service manager told me the water pump needed to be replaced ($384) because air got into the system. I asked if that was why I could hear "sloshing" from the engine when driving; he said yes. I explained that I was confused since the coolant recovery tank never went below the low line. His response was that air in the system was a known problem for the Prius and that I should keep the coolant level higher than marked. Also that driving in the South Carolina mountains -- both the heat of the engine and the angle of ascent and descent -- is probably what triggered the problem. Prior to both trips, the car was checked by a mechanic. Fluid levels were clear and adequate. I am now in the flatlands of Texas, and I can once again hear the sloshing sound coming from my engine. Beyond the expense I am concerned that the engine is completely stalling. If this were to occur in rush hour in a crowded city I'm not sure the car would be safely navigable to the shoulder.

- Seguin, TX, USA

problem #41

Nov 072009


  • 64,020 miles
2004 Prius: After driving at 10mph on gravel road with potholes and then turning on to smooth paved road engine speed and speedometer started to vary wildly with speedometer going up to 45mph down and back up again for a 5 minute period while driving on the paved road at about 30mph. This continued but car itself did not accelerate abnormally despite change in engine speed and wild speedometer.

- Chapel Hill, NC, USA

problem #40

Nov 012009

Prius 4-cyl

  • 68,000 miles
About 40% of the time, my Toyota Prius doesn't want to stop or slow down when the brakes are applied. Under these conditions, I have to apply the brakes hard and then the car will slow down. It feels like the car wants to "run away" when the brakes are applied. It exhibits this behavior in many circumstances: Stopping at a stop light, slowing down on an expressway, or slowing down on a city street. Updated 11/23/09 the check engine light illuminated. The passenger front window switch wasn't opening or closing the window unless the master switch was used. The throttle body had to be cleaned. The fan belt and brake light switch were replaced. Updated 11/24/09 updated 01/06/10 updated 01/07/10.

- Miami Beach, FL, USA

problem #39

Sep 072009


  • 73,250 miles


2004 Toyota Prius. Driving at 70 mph on I-57 North. While driving the gasoline engine stopped functioning, triggering several warning lights. I pulled the car off to the side of the highway and managed to exit the highway on battery power. There was a recall in 2005 for a similar condition. My Prius had the recall work performed in October 2005 for the software problem. The Toyota dealer is unable to find any reason for the problem and can not replicate the engine failure. As a result, they will not perform any further investigation or maintenance on the vehicle for this problem. I have a case pending with Toyota customer care, but do not expect any further assistance from them. I am also being charged labor for the dealer to inspect the vehicle. There was no fire or property damage, but if I had not been in the right hand lane, I very well could have been in a serious accident. Suddenly loosing power at highway speeds is unacceptable. If they are unable to remedy the situation, I will be returning the vehicle to them.

- Chciago, IL, USA

problem #38

Apr 082008

Prius 4-cyl

  • Automatic transmission
  • 34,000 miles
2004 Prius stalled while driving. Towed to dealer who found no problem.

- San Diego, CA, USA

problem #37

Feb 252008

Prius 4-cyl

  • Automatic transmission
  • 6,500 miles
2004 Toyota Prius stalling. After speaking w/ the Toyota consumer helpline, I've learned that the could put a program in the computer that gives you enough time to pull to the side of the road before you stall. I responded that there isn't always a shoulder to pullover to. I started getting warning lights at 6,500 mi. I now have 36,880 mi. In the beginning, the lights were just a joke or a nuisance when I had to bring it in to the dealer. On Nov 11, I stalled along w/ warning lights. You can pull over and shut it off, wait a minute, restart and drive home with warning lights, but they go out when you start up to go to dealer. I brought it to them anyway, but after they looked at the codes I was told it was soft codes and that there was nothing that they could do further. In Dec, I got the warning lights, but no stall. I drove to work and back and the lights went out when I started up to go to dealer. Feb 25 6:30 pm in the merge lane of the I-10, where there isn't a shoulder and cars are coming 40 to 50 mph into the lane to exit. How I didn't get rear-ended, I can't explain. Turned key off, restarted and drove home. Lights went out when it came time to drive to dealer Sunday night for them to check out mon am. I'm trying a new dealer Thursday and I have contacted Toyota consumer line for assistance. I not sure how far anyone can fix this issue. The service dept has updated the computer and has given me a new computer, but they don't have an answer when I inform them that this is getting dangerous, now.

- Harahan, LA, USA

problem #36

Sep 192006

Prius 4-cyl

  • Automatic transmission
  • 34,000 miles
: the contact stated while driving 30 mph the vehicle intermittently stalled without warning. This occurred on three occasions. The vehicle was maneuvered off the road and towed to the dealer each time where the problem could not be duplicated.

- Quincy, MA, USA

problem #35

Oct 142005

Prius 4-cyl

  • Automatic transmission
  • 30,800 miles


My Toyota Prius 2004 VIN [xxx] engine suddenly stalled on the freeway. I still can't restart the engine. As of 10/17/05 dealer still can't find the reason. Updated 07/18/2012 information redacted pursuant to the Freedom Of Information Act (FOIA), 5 U.S.C. 552(B)(6)

- Riverside , CA, USA

problem #34

Sep 222005


  • Automatic transmission
  • 46,500 miles
The caller said while driving at 40 mph the vehicle stalled. She was able to get off the road. Had to have the vehicle towed to dealer, who did not know yet what the problem was. Manufacturer has not been contacted yet.

- Tracy, CA, USA

problem #33

Sep 192005


  • Automatic transmission
  • 12,000 miles
I was driving on the highway at between 40-55 when the engine stalled. I tried to restart it, but it would not start. The car had to be towed. There is a one-week wait on its repair. This happened approx. 240 miles from home. This is the second time this has happened. Prius 2004.

- Portland, OR, USA

problem #32

Jul 032005


  • 50 miles
Per consumer call with C. rose (ODI) on 9/29/05 July 2004: She was backing out of driveway and went from reverse to drive without stepping on brake and started to pull forward and the vehicle stalled/ cut off. Could restart all times. July 6, 2004: Stopped at a stop light and started to accelerate to about 10-20 mph for about 1 minute when the vehicle went into neutral; gas engine stalled, but she had electric power, but said neutral; thinks stepped on brake and pushed power (starter) button 1-2 times and was able to continue driving the vehicle at full speed. July 13, 2005: Happened 2 times - driving on a crowded city street at a max of 30 mph when she noticed that the vehicle would not respond to her stepping on accelerator (panel showed neutral); able to drive vehicle no more than 5-10 mph. Pulled over immediately less than 1/2 mile. Turned it off and was able to restart right away. Drove for another minute and then the same thing happened again so she pulled over, turn off the vehicle, and restarted it right away. Did not have any additional problems that day. July 23, 2005: On the freeway going to have the vehicle looked at by dealer. She was accelerating from 45 to 65 mph, when the vehicle lost power. Vehicle continued to decrease speed. She immediately pulled over to the side of the road (believes it got down to no more than 20 mph). She stepped on brake and restarted. Not sure if the vehicle fully cut off. Brought to the dealer and they could not duplicate what happened or figure out what was wrong. Dealer called Toyota to see if this happened before and they said it did not. Dealer did not do any work on it. August 21, 2005: Backing out of driveway going from reverse to drive without engaging brake, vehicle stalled/ cut off.

- Los Angeles, CA, USA

problem #31

Jul 122004

Prius 4-cyl

  • Automatic transmission
  • 2,036 miles
Vehicle stalled while driving approximately 25-30mph on surface street with 1/4 tank of gas remaining.

- Redondo Beach, CA, USA

problem #30

Aug 062005


  • Automatic transmission
  • 11,000 miles
2004 Toyota Prius. While driving 55-60 mph vehicle constantly lost power. The engine check light came on. The consumer had difficulty restarting the vehicle.

- San Mateo, CA, USA

problem #29

Jul 072005


  • 19,000 miles
Was driving home at approximately 50mph when the 2004 Prius suddenly shut down and was inoperative. We pulled the car over, waited about 15 minutes, and was able to restart. The motor.

- Sterling, VA, USA

problem #28

Jun 272004


  • 22,400 miles
Approaching entrance ramp to I495 N exit 32 westford MA at modest side street speed 25-40 approximately. Car rapidly lost acceleration. Continued for about one minute onto the interstate and stalled on the shoulder. Battery indicated showed only one bar. Gas at least 1/3 full. Electric windows and displays and lights worked. Certain warning indicators were lit including red danger triangle. Could not turn off the power or remove the key. After 20-25 minutes, while waiting for the tow trunk, I was able to power off and on and then the car started and I drove home (30 miles). Performance appeared normal but the red triangle and a few other indicators remained lit.

- Newton, MA, USA

problem #27

Jun 282005

Prius 4-cyl

  • Automatic transmission
  • 10,500 miles
My 2004 Prius "died" with little warning while I was driving about 40 mph on a busy street. I coasted to a stop with cars flying by me. Very dangerous. Car was towed to the dealer, who explained there was a software problem and they reprogrammed the car's computer. This is an extremely dangerous problem! I'm afraid to drive this car.

- Rockville, MD, USA

problem #26

Jun 132004

Prius 4-cyl

  • Automatic transmission
  • 5,000 miles
While driving at a steady pace, the vehicle stalled.

- Bradstone, OR, USA

Read the next 20 complaints »

Not what you are looking for?