Hyundai Sonata brake failure problems

Filed Oct 28, 2026 · Brakes, Electrical · CO

On Wednesday, October 21, 2026, our 2015 Hyundai Sonata with the 2.4L Theta II GDI engine suffered a sudden, complete engine seizure while traveling about 75 mph on I-25 Southbound near Castle Rock, CO. A family member was driving. Warning lights across the car began flashing, the engine made a loud grinding noise, and the brakes stopped working. Over a long distance, the driver was able to get the car onto the shoulder and bring it to a stop, then engage the parking brake. There was no collision and no injuries, only because traffic was light. The car was towed to a repair shop, then transferred to a second shop, which determined the engine had seized and requires full replacement. This vehicle is covered by Hyundai's Theta II GDI engine campaigns for connecting rod bearing failure. On October 26, 2026, Hyundai told us the Knock Sensor Detection System software update (Campaign 953) was never completed on this vehicle and declined coverage. Neither we nor the prior owners, who are family members, recall receiving any notice of this campaign. All previous check engine lights were diagnosed and repaired at independent shops, including an intake manifold replacement in April 2024, and no shop ever identified an open engine campaign. A full engine seizure at highway speed, combined with the loss of braking, creates a serious crash risk for the driver and surrounding traffic.

Filed Sep 15, 2026 · Brakes, Engine · 140,000 miles · LA

The contact owns a 2022 Hyundai Sonata. The contact stated that the vehicle was repaired under the federal safety agency Campaign Number: 25V796000 (Fuel System, Gasoline); however, while driving 70 MPH and depressing the accelerator pedal, the vehicle decelerated unintendedly. The check engine warning light illuminated. The contact stated that upon depressing the brake pedal, the brakes failed to respond as intended. The manufacturer was notified of the failure and stated that the contact would receive a callback. The failure mileage was 140,000.

Filed Jul 18, 2026 · Brakes, Electrical · TN · fire

I was heading to work when suddenly smoke started pouring from the air conditioning vents, and the ABS and traction control warning lights came on. I hit the brakes to pull over, only to realize I had lost braking power. I managed to steer to the side of the road as carefully as possible and bring the car to a stop—despite having no brakes and a fire burning under the hood. I tried downshifting to slow the vehicle, but the transmission didn't respond, and the cabin began filling with smoke. Once I stopped, there was nothing I could do to extinguish the fire, as the car was completely consumed within seconds. It was a fire in the engine bay; I lost the brakes, and the ABS and traction control lights lit up. I assume it was a critical failure in the braking system, most likely involving the ABS module.

Filed Nov 12, 2025 · Brakes, Engine · 128,000 miles · FL

The contact owns a 2013 Hyundai Sonata. The contact stated that while driving 45-50 MPH and depressing the accelerator pedal, the vehicle failed to respond and hesitated. The brake and the hybrid system warning lights were illuminated. The contact was able to pull to the right side of the road and waited for her husband to arrive. The contact turned off the vehicle and restarted the vehicle, and the vehicle operated as intended. A dealer was contacted. The vehicle was taken to a dealer, where it was diagnosed, and determined that the hybrid ECU needed to be replaced. The contact stated that the dealer checked the error on the brake failure light that was illuminated, but had not yet gotten a response back from the manufacturer. The vehicle was taken to Auto Zone where it was diagnosed, and determined that the hybrid ECU needed to be replaced. The contact stated that the failure had occurred on several occasions for the past three years. The engine was replaced, and the vehicle was repaired. The manufacturer was not notified of the failure and informed the contact that they have not heard from the dealer. The approximate failure mileage was 128,000.

Filed Sep 23, 2025 · Brakes · GA

The issue has happened multiple times while driving, sitting in traffic, or parked idling. The Brake Light comes on and starts flashing, Alarm Chimes, Brake Pedal goes to the floor seems to not have any hydraulic pressure, the brakes grind like I have no brake pads, and essentially I have NO Brakes. If I turn the car off and on it goes back to normal. I took it to have it checked for a diagnostic code, there were none.

Filed Aug 20, 2025 · Brakes · MO

Sudden brake failure while driving at speeds around 40 mph, where both the accelerator and brakes became unresponsive, forcing me to coast before regaining limited braking ability after repeated pumping or having to "restart" the car completely. During these events, loud grinding or dragging noises and vibrations were present. Despite adequate brake fluid levels and pad condition, the brake pedal went to the floor. Could be a potential hydraulic or booster failure. It is available for inspection upon request. I was in the car with a significant other at the time of the incident, this happened around 9 times on a very busy highway during a rush. I have been able to reproduce the problem on my own but has now been inspected by a dealer or independent service center. Online resources indicate others with the same symptoms under same conditions have. The component has not been manufacturer, police, insurance representatives or others. But I have very recently (around 4 months ago) passed a vehicle inspection. There were no warnings or other symptoms prior to failure, it's very sudden and having no idea when and where it would happen makes the car inoperable.

Filed Aug 15, 2025 · Brakes, Electrical · MO · fire · 1 injury

I was driving I seen smoke then full flames on my windshield and I tried to stop and put my car in park to get out but my brakes stopped working and I couldn’t get the gear in park so I opened the driver door and had to jump out of the car .I had an engine replacement a year before for it being recalled and police and firefighters were on scene after incident

Filed Jan 15, 2025 · Brakes, Driver assistance · FL · 1 injury

Location: [XXX] Description of Incident: On a rainy morning, while driving to work, I encountered a sudden lane cut-off by a speeding truck as I exited a school zone. I applied the brakes to avoid a forward collision, but the brake system failed entirely. This resulted in the loss of vehicle traction, causing the car to spin out uncontrollably. The vehicle collided with an island, bounced into oncoming traffic, and sustained severe damage, including: •Tires ripped off the rims •Front axle damage Injuries: I sustained a lightly sprained neck as a result of the incident. Vehicle History: The vehicle had been in the custody of the Hyundai dealership just days prior to this incident for an engine/powertrain recall and replacement. The dealership held the car for over a week to address the issue. However, shortly after retrieving the vehicle, the brake failure occurred. Observations and Concerns: •The brake failure occurred after recent service by the manufacturer dealership. •Hyundai vehicles are known to have documented brake system issues, which may have contributed to this incident. •This failure nearly resulted in a life-threatening accident. Action Requested: I am requesting an investigation into the service performed during the recall and the brake system failure. It is imperative to determine accountability and address any potential defects to prevent future occurrences. [XXX] [XXX] - Victim and incident reporter. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Nov 23, 2024 · Brakes · NY

On November 4, 2024 while coming to a stop in traffic, the brake pedal went to the floor without any warning. Just prior to using the brakes, there was no feeling of softness in the pedal, and no indication a low pedal situation, and there was no indicator of pending brake failure. The brake light indicator only lit when the brake pedal went to the floor. I was fortunate that I did not rear end the vehicle ahead, or more seriously had there been a jay walker, because i quickly pumped the brake pedal with what little braking I had while shifting the automatic transmission to second gear. I was able to slowly drive ten miles home in second gear while using the hand brakes. eom

Filed Aug 2, 2024 · CA

I was driving at approx 30mph and all of a sudden I get a warning on my dashboard that says "Hybrid System Warning - Check brakes- safely stop and do not drive". My car slowed down and the brakes went to the floor. I was able to coast it to the side and turn off my car. I waited a few minutes, turned it back on and it was fine. The same thing happened 3 months ago. I took it to the dealer the first time it happened and they replaced the 12v battery and cleared all the codes. They couldn't find out exactly what was wrong. Suggestion was if it continues, then replace the hydraulic module for over $5k. It did happen again, but didn't take it to the dealer, but to a local mechanic. They checked the brakes and are fine. The codes were the same and said it might be the Hydraulic Booster High Pressure Accumulator (HPA). I was reading the Hyundai forum and this seems to happen to many Hyundai hybrids. I'm concerned for my safety and the safety of others if I was driving on the freeway and the same thing happens. There's no advance warning. I could cause an accident because of it. Seems that Hyundai needs to issue a recall on the hydraulic module and replace it.