2015 HYUNDAI SONATA Complaints

On the highway, my 2015 Hyundai Sonata suddenly began making a squealing or metallic rattling noise. At first, I thought it might have been something loose inside the vehicle. Within moments, the check engine light began blinking, followed by several additional warning lights and a pronounced knocking noise from the engine area. Immediately after the warning lights appeared, the vehicle entered a reduced-power “limp mode” and began rapidly losing speed, even though the engine was still running. Because this occurred at highway speed while surrounding traffic was traveling normally, I had to pull onto the shoulder to avoid being struck. This created a significant safety hazard. I was stranded for approximately 45 minutes on the shoulder, at risk of being struck by other vehicles passing at high speeds. A tow truck arrived before the highway patrol, and the vehicle was towed home. When I returned home, my code reader pulled two versions of diagnostic code P1326, which is associated with potential engine bearing failure in Hyundai Theta II engines. The issue has since been inspected by the dealership, who confirmed the presence of the P1326 code. The vehicle is currently available for further inspection upon request. There were no prior symptoms that I was aware of leading up to the incident other than the brief squealing/rattling noise and the sudden warning lights immediately beforehand. The failure happened suddenly and without warning, causing an immediate and unexpected loss of speed and creating a dangerous situation on the highway.

At about 30mph the sunroof suddenly flew of of my car and almost hit the car behind me thst had to avoid the flying part, for a good luck it didn’t cause a major accident because I was about get in a busy highway and this hazard could’ve caused a major ctash envolvimg multiple cars, the vehicle behind me has a dashcam that recorded the event. For God nobody got injured.

1. Description of Safety Problem: My vehicle experienced a sudden catastrophic engine failure while driving, resulting in a complete loss of power and severe engine knocking. This is a known safety defect related to the Theta II engine (specifically, connecting rod bearing failure, often referred to as the KSDS defect) that poses a severe risk of stalling and engine fire. The failure rendered the vehicle inoperable and unsafe. 2. Manufacturer's Failure to Honor Safety Recalls & Warranty: Despite this being a known, documented defect covered by Hyundai's own Technical Service Bulletin (22-EM-00H-1-1) and the TXXI Class Action Settlement—which provides a "Limited Lifetime Warranty" for this issue—Hyundai Motor America has repeatedly and wrongfully denied my warranty claim. Furthermore, I discovered through Hyundai's official campaign portal that my specific VIN had multiple unperformed safety and service campaigns, including critical Engine Control Module (ECM) updates (Campaign #953) designed to monitor and prevent this exact type of engine failure. Hyundai's failure to ensure these critical updates were performed constitutes negligence and directly contributed to the safety failure I experienced. 3. Evidence of Manufacturer Bad Faith: I have obtained documented proof that Hyundai has approved and performed zero-cost engine replacements for the identical defect on vehicles with mileage exceeding 180,000 miles. This proves that my denial is arbitrary, discriminatory, and demonstrates a pattern of bad faith in applying their safety-related warranty extensions. 4. Escalating Consequences: Due to Hyundai's refusal to honor its warranty, the dealership has now threatened a mechanic's lien and is charging $50 per day in storage fees. The manufacturer's failure to address a known safety defect is now causing active financial harm. 5. Requested Action: I urge the NHTSA to: Investigate Hyundai Motor America's systemic failure to honor the safety warranties and complete

The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at 40 MPH, there was an abnormal sound coming from the engine before the vehicle stalled. The contact pulled over to the side of the road. The check engine warning light was illuminated. A dealer was contacted. The vehicle was taken to the dealer, where it was diagnosed and determined that the knock sensor had failed, and that the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure and offered a buyback. The approximate failure mileage was 155,000.

The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at 40 MPH, there was an abnormal sound coming from the engine before the vehicle stalled. The contact was able to pull over to the side of the road. The check engine warning light was illuminated. A dealer was contacted. The vehicle was taken to the dealer, where it was diagnosed and determined that the knock sensor had failed, and the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure and offered to buy back the vehicle. The approximate failure mileage was 155,000.

Engine malfunction putting my safety at risk. This is a known issue under Hyundai’s active campaign, and the issue was verified by the manufacturer. A PA was required and Hyundai is refusing to repair vehicle due to service records prior to my ownership not being available. This issue was identified on 9/4/2025.

I was driving (I4 highway) when my car suddenly stalled, causing engine failure and almost putting my life at risk, causing an accident. This car has a factory recall for engine damage. I took it to the dealer, and Hyundai refuses to accept the engine repair because the title is rebuilt. The car has no damage to its original engine and is ready to be replaced. They don’t want to assume responsibility.

I am reporting a recurring and unresolved hybrid system failure in my 2015 Hyundai Sonata Hybrid Limited that poses an ongoing safety risk to me and my family. The issue involves a "Hybrid System Warning – Safely Stop and Do Not Drive" message that appears randomly while driving, causing the vehicle to jerking and creating dangerous conditions on the road. This issue first occurred in February 2024 and has persisted through October 2025 despite repeated service visits and costly out-of-pocket repairs. The hybrid battery was eventually replaced after 8+ months of delays, but the exact same warning and jerking symptoms returned in March 2025 and have never been properly resolved. The dealership (Crown Hyundai in St. Petersburg, FL) and Hyundai corporate case management have been unable to replicate or diagnose the problem consistently, and continue returning the vehicle to me in unsafe condition. On October 3, 2025, the same warning reappeared and the vehicle was dropped off again for yet another service attempt. Again on October 7, 2025, I was told to pick up my car, they could not replicate the issue and could not find a code to respond to. To date, I’ve paid $1,748.65 for a repair (air flappers) that did not solve the issue, and spent months without use of the vehicle, continuing to pay for insurance during that time. I believe this is a defective hybrid propulsion system that meets the threshold for investigation and possibly a recall, given the repeat safety risk and lack of resolution. Please investigate this matter for the safety of other drivers as well.

What the consumer services tried to offer (More Information for case)me, instead of a replaced engine that is under my warranty. They have replaced engines before over the mileage as goodwill warranty, but refuse to do the necessary work because of mileages. KSDS is designed for any mileage, and they put a mileage limit on the vehicles warranty, that not just I, but multiple people purchased; where the justice

While driving, my 2015 Hyundai Sonata 2.0T experienced severe knocking and loss of power due to a KSDS-related engine defect. The check engine light was inoperative, and the engine now makes loud noises and emits fumes. Hyundai declined warranty coverage despite known KSDS issues. This poses a serious safety concern ( I recently purchased the car and been fixing problems every since)