fairly significant
Crashes / Fires:
0 / 0
Injuries / Deaths:
0 / 0
Average Mileage:
14,848 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.

2012 Toyota Prius engine problems

engine problem

Find something helpful? Spread the word.
Get notified about new defects, investigations, recalls & lawsuits for the 2012 Toyota Prius:

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

2012 Toyota Prius Owner Comments

problem #9

Jul 142016


  • 37,765 miles


The contact owns a 2012 Toyota Prius. The contact stated that while driving at 65 mph, the vehicle stalled as the master warning light illuminated. The vehicle was towed to the dealer. The technician was unable to diagnose the failure and stated that the only code found was related to low fuel although the vehicle had a full tank of fuel. The manufacturer was made aware of the failure and made the contact was made aware that the vehicle was not included in NHTSA campaign number: 14V053000 (electrical system, hybrid propulsion system). The vehicle was not repaired. The failure mileage was 37,795.

- Mansfield, TX, USA

problem #8

Jul 292014


  • 14,000 miles
After Toyota power management software recall installed "power management upgrade" software in my car I immediately experienced serious problems with my ignition /start of hybrid/gasoline engine. After pressing ignition, I had to wait 15 to 20 minutes and press start button on/off repeatedly until the gasoline engine ignite but hybrid failed to start. It is not normal because a Prius hybrid engine starts first not the gasoline engine. Toyota has disabled some important functions in its power management recall software update that affects the hybrid engine performance and failure to start. I drive my Prius 3-4 times a month and I did not have any problem before the recall software upgrade because Prius owners manual clearly says that the battery with be disconnected by battery saving function when your car is parked for long time, several days, weeks. In fact, when your car is parked for just days, Toyota power management software (recall) is draining the car battery and reconfiguring the relays to power up the gasoline engine. Toyota owners manual clearly states that when you are parked, "power management software disconnects the auxiliary battery from the hybrid system." However, after the recall, not only auxiliary battery is not disconnected but there are lots of "activity" in hybrid engine that drains the batteries. I called the Toyota service and they now say you have to keep the car on a charger all the time when parked for several days. Of course, it is a huge safety problem to keep the car on a charger all the time when parked for days because the battery is housed in the cabin and the ventilation does not exist unless you park your car outdoors. At the same time Toyota recommends keeping the car on a charger, it also warns of explosion caused by charging the batteries in a garage.

- Scotts Valley, CA, USA

problem #7

May 012013


  • miles
Starting in spring 2013 and continuing during the rest of the spring, summer and early fall in the hottest months, after parking my Prius C outside, it always had issues starting, which continues to this day. I will put the key in the ignition, start the car, all the dash lights come on and the car will usually not allow me to put it into reverse or drive. I have to take the key out of the ignition and start it again at least twice before it starts normally as it does when the weather is cooler and/or when the car is parked in my garage. A couple of times, I managed to get the car to go into reverse, but it was almost impossible to steer as if the parking brake was on. Then the vehicle stopped, leaving me in the path of oncoming traffic. This has been happening since I bought the car and the dealership says they can't fix it unless they can recreate the problem. I have taken pictures and viseo, but that makes no difference to them. This is a dangerous problem and needs to be fixed. This is the second complaint I have filed re: This matter as my first does not seem to appear here.

- Peoria, AZ, USA

problem #6

Apr 222014

Prius 4-cyl

  • 31,000 miles


Driving the interstate at 65 mph the engine stopped - with no warning of any kind, the air, dash lights, radio, etc all continued to work. We coasted to the side of the road & restarted the engine. We purchased new & had all the required maintenance done at the Toyota dealership. We learned of a recall on the news in February & took the car in for the repair. (a software problem related to the car engine stopping while driving) when we learned of the recall we remembered this had happened to us about a month earlier, again, on the interstate at 65 mph & thought it was just a fluke at the time. We were very upset when this latest incident happened after having the recall repair done on the car & having driven a few thousand miles between incidents. We drove the car directly to our dealer's service dept and reported these facts to the service manager. They immediately took it in and tried to detect any evidence of the incident. They told us that they also contacted Toyota corporate technical services for assistance. They were not able to find any evidence of the incident. As we are now afraid to drive the car, they gave us a car to drive until the problem could be resolved. We don't want to see this car sold to an unsuspecting driver. We feel this is a life threatening defect and Toyota should repurchase the car from us at a fair value so that we could replace it with another car. We contacted the Toyota customer experience center yesterday by phone and filed a formal complaint, they opened a file and gave us a case number. Today we were contacted by phone by a Toyota regional analyst and were told that since they cannot find any evidence of the incident by using their computer system we would need to file a lemon law complaint. We told him that we expect Toyota to resolve our issue - we should not have to prove the defect. Help.

- Peachtree City, GA, USA

problem #5

Jan 032014

Prius 4-cyl

  • 32,775 miles
The contact owns a 2012 Toyota Prius hybrid. The contact stated that the automatic startup engaged independently with a loud clunking noise. The vehicle was towed to an authorized dealer for diagnosis. The technician was unable to duplicate the problem. The vehicle was also diagnosed by a different dealer who refused to repair the vehicle. The manufacturer was notified of the problem. The vehicle had not been repaired. The approximate failure mileage was 32,775...updated 02-28-14 the consumer stated the vehicle was traded in. Updated 03/19/2014

- Spanaway, WA, USA

problem #4

Jun 012013

Prius 4-cyl

  • 3,000 miles
Moldy odor emits from vents. Had round rock Toyota dealership attempt to correct the issue four times and also had called up Toyota Corp but issue was never resolved. On the fourth attempt at the dealership, Toyota had authorized a carbon-type cabin filter that was suppose to be able to remove the odor but it did not help. Did not fix or replace the root cause of the issue. Food was never allowed in this vehicle; air vent was selector for fresh (not recirculate). This is my third but last Toyota. It breaks my heart to have purchased a brand new Prius and by 3000 miles, strong moldy odor exists. Dealer had sprayed lysol, provided ac refresh kit but evaporator or ventilation system is faulty. Toyota bulletin # T-sv-0142-13 (Sept 12).

- Round Rock, TX, USA

problem #3

May 082012

Prius 4-cyl

  • 600 miles


1. when vehicle transitioned from battery to motor, significant impact resulted 2. brake pedal traveled to floor, dash warning light came on [vehicle towed] 3. attempting to leave dealers lot, brake pedal traveled to floor. Technician witnessed. Updated 01/15/13

- Middleboro, MA, USA

problem #2

Sep 032012

Prius 4-cyl

  • 4,944 miles
Driving 70 mph car began to go into high RPM, then accelerated to 74 from 70 mph. I tried to decrease speed then vehicle shut off got a long beep and message on display "check hybrid system, pull over immediately" all lights on dash were indicating failures. Coasted to safety with 5 passengers in vehicle across traffic at 9:30 pm to shoulder. Tried to restart several times then vehicle went into high RPM then engine knocked loudly and was completely disabled. Lost brakes, pedal was hard, lost power steering, difficult to maneuver. I still had 2 bars indicating plenty of fuel in car. Prior fillup was 7.6 gallons at pump, usually get over 500 miles per tank, trip meter only showed under 400 miles since fill up so had plenty of fuel and there was no low fuel indicator. Reported all problems to dealer. They only noted the car shut down but told me they confirmed everything I said and that Toyota engineers are trying to resolve this since they are aware of this type of problem. So far dealer and Toyota have not addressed the high RPM, the acceleration, loss of electronics and hybrid system failure and told me they havenever heard of any Toyota ever having a report of a high RPM or acceleration without intent to accelerate form the driver. Vehicle is unsafe, has 4944 miles and this problem occurred about a month after purchase. Toyota still does not know what the problems are and in possession of the vehicle.

- Menifee, CA, USA

problem #1

Aug 242012

Prius 4-cyl

  • 9,550 miles
Hybrid engine suddenly shut down without warning while vehicle was traveling 65 mph on a busy freeway, causing vehicle to come an unsafe stop. Depressing accelerator had no effect. Onboard computer gave error message "check hybrid system. Stop the vehicle in a safe place." Restarting vehicle produced the same error message and still unable to shift vehicle into drive or reverse. Fuel tank full at time of incident. Vehicle purchased new 5 months prior from Toyota dealership. No aftermarket parts or modifications present.

- Rolling Hills Estates, CA, USA

Not what you are looking for?