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.
The worst 2018 Toyota Prius Prime problems
Ranked by number of owner complaints. Mileage and cost come from what owners wrote.
- Airbags2
- Fuel system2
- Transmission2
- Visibility2
- Acceleration1
Problems by type
Tap a problem to see which part fails, at what mileage and in which other years.
- Airbags2
- Fuel system2
- Transmission2
- Visibility2
- Acceleration1
- Body1
- Brakes1
- Driver assistance1
- Electrical1
- Engine1
- Lights1
- Locks1
Recalls
No recalls on record for this model year.
Defect investigations
Pedestrian alert sounds
the federal safety agency received a petition on or about July 18, 2022, requesting that Federal Motor Vehicle Safety Standard (FMVSS) 141 be applied to all electric and hybrid vehicles operating in the United States. The petition can be reviewed at under ODI Number 11486072. FMVSS 141 establishes performance requirements for pedestrian alert sounds for motor vehicles. The standard applies to hybrid and electric vehicles that have a gross vehicle weight rating of 4,536 KG or less or are defined as low-speed vehicles. The standard became fully applicable to all such vehicles manufactured on or after March 1, 2021.On January 27, 2023, the federal safety agency opened Defect Petition (DP) 22-005 to evaluate the subject matter described in the petition. On June 24, 2023 and as supplemented on June 25, 2023, the petitioner notified the federal safety agency he was withdrawing his petition. The petitioner indicated that, based on his review of data, there is no justification for asserting potential benefits that could be derived from actions sought by my petition. Based on the petitioner's withdrawal, DP22-005 is closed. Closure of this DP does not represent a determination by the federal safety agency regarding the subject matter of the petition.
DP22005
Technical service bulletins for the 2018 Toyota Prius Prime 98
Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.
- Condition in which a musty odor is present
- Some ECUs can set a DTC that is common with other ECUs. This can lead to accidental use of the wrong...
- The air conditioning dye injection tool kit has been developed to aid in identifying the location of air...
- Acid rain results from rainwater or other airborne moisture that become acidic due to industrial chemical...
- To prevent brake rotor rust from forming during transportation and storage, wheel film will be used...
- The condition known as acid rain is caused by airborne chemicals or particles in the atmosphere, which mix...
- Toyota vehicles are currently protected with RapgardTM protective film designed to protect the horizontal...
- Vehicles may occasionally be subjected to contamination by airborne iron particles shed from railroad...
- Condition in which a musty odor is present
- Toyota vehicles are currently protected with RapgardTM protective film designed to protect the horizontal...
2018 Toyota Prius Prime fuel economy
Official EPA estimates in miles per gallon (MPGe for electric). Ranges cover trims that share the same engine.
| Engine | Drive | City | Highway | Combined |
|---|---|---|---|---|
| 1.8L 4‑cyl Plug-in hybrid | FWD | 55 | 53 | 54 |
What 2018 Toyota Prius Prime owners say
Most recent owner complaints, unedited.
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.
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 federal safety agency 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. the federal safety agency, please step in
As I was driving on a local highway going approximately 50 mph, the hood of the vehicle released and hit the windshield with full force. Luckily there was no traffic on the local highway at the time of the incident. I did not release the hood at all, and the dealer reports verbally to me that the hood latch is damaged. The incident could have resulted in my death if it happened on the highway.
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.
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
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 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.
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.
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.
Compare the 2018 Toyota Prius Prime
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Questions about the 2018 Toyota Prius Prime
Is the 2018 Toyota Prius Prime reliable?
Owners have filed 16 complaints about the 2018 Toyota Prius Prime, 1.6 times a typical Prius Prime model year.
What is the 2018 Toyota Prius Prime year score?
The 2018 Toyota Prius Prime scores 55 out of 100 (below average). The score compares it with the other model years of the Toyota Prius Prime: 75 is a typical year, 50 means twice the usual complaints, and serious complaints and recalls lower it.
What is the most common problem with the 2018 Toyota Prius Prime?
Airbags, with 2 complaints. Next is fuel system (2).
How many recalls does the 2018 Toyota Prius Prime have?
No recalls on record.
What gas mileage does the 2018 Toyota Prius Prime get?
Official estimates for the 2018 Toyota Prius Prime range from 54 mpg combined. The most efficient version (1.8L 4-cyl plug-in hybrid, FWD) gets 55 city and 53 highway.
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