Toyota Prius check engine light comes on

Filed May 19, 2026 · Engine, Fuel system · PA

The catalytic converter heat exchanger failed internally, causing coolant to leak into the exhaust system. Symptoms included white smoke from exhaust and coolant loss with no visible ground leak. This is a documented factory defect per Toyota Technical Service Bulletin T-SB-0135-19 affecting 2016-2019 Prius models. Toyota has denied warranty coverage despite the vehicle was originally bought & spent its entire prior operational life registered in New York, a state covered under Toyota's full 15-year/150,000-mile emissions warranty. Defect was confirmed by an authorized Toyota dealership, in PA. Vehicle had approximately 83,104 miles at time of diagnosis. Manufacturer denied coverage and is forcing the customer (me) to pay a huge amount for this very well known & defective case. MOST IMPORTANTLY ITS dangerous and unsafe for all the cars our there too, since it is very well known that at a certain point this will happen, but despite TOYOTA never sent a RECALL. Due to this, engine light goes on & off, refrigerant is flammable and leaks in the exhaust pipe happens with this specific case, which ultimately could catch on fire, while the vehicle is moving or stalling. Lots of white smoke comes out of the car that directly impact the environmental aspects, and above all, people owning such vehicle, will be running into this issue, which will 100% put the safety of owner and anyone close in proximity to their vehicle at RISK. PLEASE ADD RECALL WITHOUT CAP for ALL SUCH TOYATA PRIUS due to flammable refrigerant leak inside the car engine components, and proven via strong white smoke coming out of exhaust that has the potentially to put the entire car on fire, specifically.

Filed Mar 6, 2026 · Fuel system · AR

For the last 14 years, a check engine light has been coming on telling me that I have a fuel canister emissions leak because the canister is cracked. In 2016 2.87 million Toyota Priuses were recalled with the fuel canister crack issue. For unknown reasons Toyota has refused to fix this dangerous issue and has told me that my car was NOT included in the recall. I do not believe Toyota is being honest in their continued denial of this dangerous issue and excluding my 2010 Toyota Prius. This issue has been ongoing since the car was new.

Filed Mar 1, 2026 · Acceleration · OH

The way the accelerator pedal sensor is positioned allows for water infiltration from wet carpet / tracked in snow and water. The component is available for inspection upon request. Once sufficiently saturated the sensor fails, and ceases function DURING VEHICLE MOVEMENT. The problem is reproducible but has not been confirmed as a pattern of failure by the dealership. As far as my recollection, the manufacturer hasn’t inspected the part. P2138 is the associated check engine code and the vehicle enters limp mode DURING TRAVEL. The check engine light (and subsequent problems) first appeared while in traffic on 2/10/2026.

Filed Feb 9, 2026 · Brakes · FL

I was driving and notice ABS light and other light came on, then noticed that when I tried to brake it felt weak, had to pump brake, then later noticed a leak on brake fluid. I took car to Toyota and they checked it and said brake booster and booster pump needed replacing and they wanted to charge me 3,000 dollars. I could not do the job so I checked around and the auto one in my area informed me that many Toyota Prius’s had a recall on that issue. I made an appointment with Parks Toyota in Deland, Florida to fix problem but when he got there they told me that my car was not on recall for that but was for battery EV fuse but couldn’t do because my engine light was off. I am having such a difficult time with this car. I cannot risk my life and that of others driving with this brake condition if I can’t have the manufacturer or who ever has to to take care of this issue. So far I was able to get a mechanic to do some adjustments so I can drive. I am being very careful and only use it as needed. I stopped looking for a part-time job because I need this fixed first. I am [XXX] , please tell me if I am able to get this recall show for me. Thanks INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 7, 2026 · Brakes · CA

Vehicle check engine code C1391 (Antilock Brake System - abnormal leak in accumulator) came up on 2/5/2026. Recommended repair is to replace the Brake Booster Pump and Assembly, Brake Booster - over $1000 in parts alone. This WAS covered by an Extended Warranty by Toyota (10 years / 150K miles). I only have 120K miles at this time but am past the 10 year mark. However, it seems that this part will fail in every Prius given time and encourage the federal safety agency to monitor these failures and hold Toyota accountable to address post the 10 year / 150K mile mark.

Filed Jan 15, 2026 · Electrical, Engine · MD

I was driving my car at over 70 mph on a highway, no check engine, no issues, just had oil changed when check hybrid system alert came on with check engine light. I started to change lanes to get to shoulder when my car just died, completely. It died in the middle of the highway merging with another major road, so I was stuck between 2 lanes of 70mph traffic on either side. The time to react to the sudden warning to my car dying was less than 2 minutes. I quickly called 911 to ask for help and was told someone had already reported my breakdown as well because my car had died in a horribly dangerous area. I was very lucky that a state trooper came quickly and blocked off my car until it could be towed for repair. I was told that I need a new Hybrid Battery. The fact that I had no signs of failure before complete shut down makes for a very dangerous driving situation and makes me second guess ever buying a Prius again.

Filed Jan 7, 2026 · Engine · OH

Crack in the Engine. I had been following the recommended Maintenance schedule, but I suddenly had issues where the engine would stall/stutter on activation (switching from electric to motor operation). The check engine light came on, and I immediately took it to the dealer who replaced the battery and spark plugs saying that was the issue. That solution did not even last a month, as I had sometimes severe shaking in the engine along with the stutter. I again brought it to the dealership who told me that the actual problem was a cracked head gasket and that the vehicle was "mechanically totaled". I was lucky that I live close to the dealership and worry what would have happened if I had to drive on it further.

Filed Dec 30, 2025 · Brakes · TX

On November 25, 2025, at approximately 11:45 p.m., our 2010 Toyota Prius experienced a braking system malfunction during normal operation. The brake pedal required significantly increased effort and the vehicle exhibited reduced braking performance, indicating a loss of brake power assist. The vehicle required increased stopping distance, creating an immediate risk of a collision. At the time of the failure, multiple warning indicators illuminated simultaneously, including the brake system warning, ABS warning, check engine light, battery warning, steering warning, tire pressure warning, and vehicle stability control/slip indicator. There were no warning lamps or abnormal symptoms prior to the failure. The failure was determined to involve the brake booster pump assembly, a component responsible for maintaining hydraulic brake assist pressure. This component is known to experience internal accumulator housing degradation, which can allow nitrogen gas migration into the brake fluid and result in partial or complete loss of brake assist. The affected component remains available for inspection. Following the incident, an authorized Toyota dealership inspected the vehicle and reproduced and confirmed the condition. Service records indicate the brake booster pump assembly had previously been replaced under a Toyota safety recall. Despite this prior recall repair, the same component failed again after approximately 41,000 miles of service, demonstrating that the recall remedy was ineffective. As a result of this failure, the vehicle was rendered unsafe to operate. Despite dealer confirmation that the malfunction involved a previously recalled safety component, corrective repairs were declined, with warranty limitations cited rather than addressing the repeat safety-related failure.

Filed Dec 2, 2025 · Brakes, Fuel system · NC

The contact owns a 2010 Toyota Prius. The contact stated that while driving 70 MPH, the vehicle jerked, and the vehicle failed to accelerate as intended while depressing the accelerator pedal. Additionally, the steering wheel seized, and the vehicle stalled. The contact pulled over to the side of the road, opened the hood, and disconnected and reconnected the battery terminals to reboot the vehicle. The contact stated that a yellow triangle warning light and the check engine warning light were illuminated. The message "Check Hybrid System" was displayed. The contact was able to restart the vehicle; however, the vehicle failed to exceed 65 MPH while driving. The ABS warning light was illuminated. The contact took the vehicle to Auto Zone and O'Reilly's; however, no cause for the failure was found. The vehicle was then taken to the dealer. The contact was informed that the failure might be an ABS system failure. The vehicle was not repaired due to the cost. The contact stated that the failure first occurred years ago, and the failure persisted. The manufacturer was not notified of the failure. The failure mileage was unknown.

Filed Nov 28, 2025 · Brakes · CA

While driving on a city road below the speed limit, braking was compromised leading to loss of traction and failure of the ABS system. During the incident, the brake, ABS, and engine warning lights all turned on and a collision was only avoided due to pumping of the brakes. Further investigation by a mechanic revealed a failure of the brake actuator system. Failure of this system has increased the stopping distance of the vehicle considerably and makes braking unreliable and unpredictable.