*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Engine
Coolant is leaking into the catalytic converter. This seems to be a common issue. Toyota issued a technical service bulletin on XXX covering this exactly. Some 2016â2019 Prius and 2017â2019 Prius Prime vehicles may exhibit low coolant level, MIL on with DTC P148F00, and/or poor heater performance due to coolant leakage at the front exhaust pipe heat exchanger. The front exhaust pipe with heat exchanger assembly has been updated. The repair is listed as a 1.5-hour remove-and-replace of the front exhaust pipe assembly, and the diagnostic procedure involves unbolting the rear exhaust pipe from the front pipe at the mating flange when everything is cold and inspecting for coolant leakage…
Aug 26, 2026Electrical system
Frequency when I start car makes a very loud , painful high pitch noise for anywhere from 5-15 seconds
Jul 12, 2026Unknown or other
Body of car has rust perforation starting from the inside working out. This is on the roof, so water incursion will effect airbags and electrical system. FIrst noticed rust bubbles a few years ago, but did not think much of it. Now two body shops have said roof panel needs to be replaced. This is big stuff!
May 1, 2024Service brakes
See Attachment
Oct 28, 2025Forward collision avoidance › Automatic emergency braking
Since October 2023, my 2019 Toyota Prius has developed severe and unpredictable driving behavior after a regular brake service, which may have triggered or coincided with a software or ECU update. The car, which had been driving smoothly since I bought it in 2021, suddenly began showing false braking, steering interference, and lane instability â as if the car were trying to âcorrectâ problems that didnât exist. These interventions often happen on highways or during turns, creating serious safety risks for both driver and passengers. Iâve spent months and thousands of dollars replacing parts, performing alignments, and recalibrating sensors, including at Toyota dealerships. The…
Oct 1, 2023Unknown or other
Coolant system failed because coolant was leaking into catalytic converter. Two mechanics in two different states (one a Toyota dealer) claimed this is defect with 2019 Prius and results in repair costing more than $2000.00 because of this design flaw. Warning light did not come on until coolant was gone.
Jul 3, 2025Engine and engine cooling
The contact owns a 2019 Toyota Prius. The contact stated there was a coolant leak and the coolant level was low. There was no indication of coolant on the ground. The check engine and engine HOT warning lights were illuminated. The contact stated that the failure was related to TSB: 0135-19. The vehicle was taken to the local dealer where it was diagnosed that there was a coolant leak in the front exhaust pipe heat exchanger. The parts to repair the vehicle were on backorder. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was approximately 95,000.
May 27, 2025 · 95,000 milesPower train
Exhaust heat-exchanger coolant pipe (part of the hybrid cooling loop) on my 2019 Toyota Prius is the system that failed. Safety risk: complete loss of coolant can cause sudden engine overheating and possible power reduction or shutdown while the vehicle is moving. I transport two young children daily; an unexpected stall on a highway or during an intersection turn would put all occupants and surrounding traffic at risk. AutoNation Toyota Mall of Georgia (dealer) inspected the car on 22-May-2025, confirmed the leak, and advised the vehicle is unsafe to drive until the pipe is replaced. Repair estimate is $2,249 parts & labor to replace the front exhaust pipe that is on back order, no ETA.…
May 22, 2025
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.
