2018 Toyota Prius Prime Complaints

POWER TRAIN — Filed 01/09/2026

On at least 4 occasions when the EV battery becomes depleted while driving at highway speeds and the car is switching to gas, the engine completely loses all power. This has lasted from 10-30 seconds. The dealership said a small battery needed to be replaced, and replaced that, but this recurred within a month of replacement.

UNKNOWN OR OTHER — Filed 12/07/2025

There has been at least 4 times that the vehicle was not responsive to acceleration (stalled for a few seconds) then picked back up. Problem has been intermittent. There is no dash indication of an issue. Because concern is intermittent I haven’t taken vehicle in. There is NO CHECK ENGINE light on. My wife experienced it once, I’ve experienced it 3 times. Once going up steep hill, once on a steady incline and the other 2 times at 50 mph on the highway. My layman’s take points to an Inverter issue in the IPM. Intelligent Power Module having a voltage issue that causes vehicle to stall.

VISIBILITY — Filed 01/02/2025

Hi, My Prius Prime recently just suffered the loss of heat in the middle of winter. Based on the diagnostic of my local Toyota dealer, it appears one of the metal heater coolant hose had rusted off. This is not just causing a safety issue of having no issue, it is also a risk as the engine can now overheat and suffer permanent damage. Despite being such a serious problem, Toyota doesn't stock the part nor does it know when the new part will come. I am currently owning an asset that can't be safely driven, I would like the NHTSA to review this. Toyota seems to be aware of this issue as they have a TSB out on a similar heater coolant hose. With that said, having no part is not an acceptable option. NHTSA, please step in

STRUCTURE,VEHICLE SPEED CONTROL,UNKNOWN OR OTHER — Filed 10/21/2023

My 2018 Toyota Prius Supreme was parked too far away from the curb in front of a house where we were invited, in a residential area in Naperville IL. I entered the car to park it properly. I had my foot on the brakes and pressed the starting button for the engine to turn on. I then put the car on reverse and suddently the car accelerated uncontollably. Went on the grass, hit the neighbor's mailbox and stopped by crashing on a tree. I was in shock but luckily not injured. Other guests were present and witnessed the incident. Police was called in and issued a report. The car was declared by Progressive Insurance Co as a total loss.

AIR BAGS — Filed 08/03/2023

Airbags deployed prematurely as I was parking my car in a doctor's office parking lot. The car was going less than 5 mph and I did not hit anything. The premature deployment of the airbag startled me and caused me to hit the accelerator instead of the brake and I ended up crashing my car into a nearby pole and another .automobile. The accident resulted in a soft tissue injury for my daughter and I'm experiencing lower back pains. The air bag caused burns on my nose and arms. My daughter has bruising on the arms from the air bag deployment

POWER TRAIN — Filed 04/14/2023

Take foot of break, car accelerates under power. Sooner or later, this is going to result in killing a pedestrian. The question has been for the last year, is this a behavior that can be gotten used to. The answer is definitely NO! This resulted in a near collision with a pedestrian today. Toyota believes the behavior is intentional and will not confirm the safety issue. Farmers Insurance is willing to believe the issue exists without inspection but has no idea what to do. You have a problem on your hands. Biden is trying to transition almost everybody away from gasoline vehicles; thus those that drive manual transmissions will be driving electric vehicles, and their brain patterns have not changed and the procedure for getting rolling from a dead stop will be done the old way, and it's now dangerous. In a manual transmission it is necessary to transition off the break before completing looking all three ways (left, right, straight) because the transition time from break to power is so long that if the looking is done before, it is out of date by the time power is being applied. Applying the same procedure to an electric car has potentially lethal results; and people who have been driving a manual transmission for a long time will end up using its procedure in an electric car by habit. Perhaps you observed the reports over the last few decades of old men with new cars having unintended acceleration problems with no cause found. I now believe that a number of these have a very similar explanation. Car isn't off, take foot of break to get out of car, car accelerates. In an electric car, telling the car isn't off isn't very easy any more. This is easy to understand. An automatic transmission vehicle has an unremovable dumb behavior where take foot off break accelerates, whereas in a manual transmission this stalls, which is a safer result. There is no reason this behavior should carry over to computer drive, including electric or hybrid vehicles.

AIR BAGS — Filed 01/11/2023

Air bag did not deploy during a head on collision at 25-30 mph. No warning lamps. Car is totaled according to tow truck driver. Currently at the body shop, waiting for adjusters approval for body shop to take car apart to assess the damage.

SERVICE BRAKES — Filed 08/31/2022

The contact owns a 2018 Toyota Prius. The contact stated while driving approximately 5 MPH and in heavy traffic, the contact depressed the brake pedal for traffic but the brakes failed. The contact stated no warning light was illuminated. The contact crashed into the rear end of a truck. The damage was very light due to the low speed. The top of the hood at the front was scratched and the grill also sustained minor scratches. The contact continued on the road. The contact had taken the vehicle to a local dealer, who contacted a manufacturer representative to diagnose the vehicle. The contact was advised that there was no brake failure. The vehicle had not been repaired. The manufacturer had been informed of the failure. The failure mileage was 40,063.

BACK OVER PREVENTION,FORWARD COLLISION AVOIDANCE — Filed 11/15/2018

From the first week of ownership sensors would alarm that they needed cleaning but they were clean. Parking assist sensors also malfunctioning. Also saw Intelligent Clearance Sonar error messages and warnings. Alarm tended to go off in wet weather. Brought to dealership many times and problem occurred infrequently that no problem was ever found. For two years I was plagued by alarms of sensor malfunction. I worried the sensors would fail to detect cars and objects in front of, behind or on the side of the car. That would be a serious failure and cause of an accident. After two years of unsuccessful testing, I traded in the car.

EXTERIOR LIGHTING — Filed 01/28/2021

WHILE DRIVING ON RURAL ROADS WITH NO STREET LIGHTS, THE AUTOMATIC HIGH BEAM SYSTEM MALFUNCTIONS WHEN PASSING ONCOMING TRAFFIC WHO DO NOT DIM THEIR HEADLIGHTS OR WHO HAVE THOSE HEADLIGHTS THAT SHOULD BE ILLEGAL (LIKE FORD). NORMAL LOW-BEAM HEADLIGHTS DO NOT CAUSE THE SYSTEM TO MALFUNCTION. I BELIEVE THIS MALFUNCTION TO BE RELATED TO THE CAMERA SENSOR LOCATED ON THE WINDSHIELD AND WHEN THE GLARE OF THE EXCESSIVELY BRIGHT HEADLIGHTS HIT THAT SENSOR, IT CRASHES THE AUTO SYSTEM. THE SYMBOL ON THE DASH THAT INDICATES THAT THE SYSTEM IS WORKING NORMAL CUTS OFF FOR APPROXIMATELY 25-30 SECONDS, DURING WHICH TIME THE HIGH BEAMS WILL NOT ENGAGE. AFTER THAT 30 SECOND DELAY, THE SYSTEM REBOOTS, THE LIGHT ON THE DASH COMES BACK ON AND THE HIGH BEAMS RE-ENGAGE. THIS IS DANGEROUS AS ALL MANNER OF WILDLIFE CROSS THAT ROAD AT NIGHT AND WITHOUT BRIGHT LIGHTS, MY REACTION TIME IS CUT IN HALF. I HAVE TALKED TO THE TOYOTA DEALERSHIP ABOUT THIS ISSUE SINCE I PURCHASED THIS CAR IN MAY OF 2019 TELLING THEM THERE IS A MALFUNCTION IN THE SYSTEM, AND WAS INITIALLY INFORMED THAT THIS WAS NORMAL FUNCTIONALITY. I OWNED A 2017 PRIUS PRIME ADVANCED (ONE YEAR OLDER THAN THIS ONE) AND IT NEVER MALFUNCTIONED, SO I KNOW THIS IS A MALFUNCTION IN THE SYSTEM. AFTER SPEAKING WITH THE SERVICE MANAGER IN DEPTH ABOUT MY EXPERIENCE WITH THIS ISSUE, HE FINALLY UNDERSTOOD THAT THIS IS AN ISSUE AND NOT NORMAL FUNCTIONALITY. THEY HAVE KEPT MY CAR SEVERAL TIMES TRYING TO RECREATE THE FAILURE, BUT UNLESS THEY DRIVE OUT IN THE MIDDLE OF NOWHERE (SUPER DARK) AND COME ACROSS SOMEONE WITH "TOO-BRIGHT" HEADLIGHTS, IT IS UNLIKELY THEY WILL ACCOMPLISH A FAILURE. I WAS ALSO TOLD THAT TOYOTA DID NOT KNOW ANYTHING ABOUT THIS ISSUE. I HAVE SINCE DONE THE RESEARCH AND FOUND THAT THIS HAS BEEN AN ISSUE SINCE AT LEAST 2017, AND OCCURS ON VARIOUS TOYOTA MODELS (PRIUS, AVALON, RAV4, ETC...). I HAVE VIDEO OF THE FAILURE.