2025 Hyundai Santa Fe

After making right turn after being stopped at traffic light, when I attempted to accelerate the vehicle would not shift from low gear to higher gear(s). This caused very high engine RPMs for the time it took to pull the vehicle off to the side of the road and stop and turn of the vehicle . I looked at dash board for any indicator lights but didn’t see any. Restarted the vehicle accelerated back on to the road and the vehicle did change gears ok. Again looking for any dashboard indicator to be on but didn’t see any. The date of this incident was [XXX]. Made appointment on 2/10/26 for service to diagnose why this incident happened on 2/17/26 and to provide any necessary repairs at Columbia Hyundai, Cincinnati, Ohio. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

I tried to drive my 2025 Hyundai Santa Fe Hybrid; the vehicle displayed a gear selection error message stating something like "gear already selected". The vehicle would not shift properly and would not power off or restart. I attempted multiple shutdown and restart attempts using the Start/Stop button with no success. The vehicle remained in this condition for about 30 minutes and would not allow normal operation or shutdown. Due to safety concerns, Hyundai roadside assistance was contacted and a tow truck was dispatched. Before the tow arrived, the vehicle spontaneously allowed shutdown without any intervention. This was a safety related failure involving the shift-by-wire system and vehicle power-down logic. The issue occurred without warning and left the vehicle inoperable. The vehicle had app 7150 miles at the time of the incident.

My 2025 Hyundai Santa Fe Hybrid has recurring powertrain communication failures starting at only 67 miles and continuing at 5,300 and 6,200 miles. Diagnostic trouble codes include U010100 (lost communication with engine control module) and multiple U100xxx codes related to transmission and CAN bus communication failures. These indicate loss of communication between critical control modules. The issue has happened multiple times and remains unresolved. I am concerned this could cause drivability problems, warning lights, or sudden loss of power. This appears to be a system-level defect in the vehicle’s communication network.

After a maintenance service was performed at 16500 miles, we began to notice a high pitched whistling sound when pressing gas pedal doing highway driving above 75mph. The car was brought back to the dealer who couldn’t duplicate the complaint. We drove cross country, sound consistent until it began to make the sound at lower and lower speeds. We arrived at our destination and I took the car to the dealer we bought the car from. Their tech claimed it was normal coil whine. Since it was progressing I had the manager test drive the vehicle who agreed it was not normal. After a week we switched service advisors who immediately determined it was a failing transmission that needed replacement Now waiting for parts to arrive. I am requesting a buyback per California lemon law

Bought this brand new Santa Fe in July 2025 and on day 5 after purchasing this vehicle, car stopped accelerating while driving on highway, which is a serious safety concern. Took the vehicle back to the dealership and turned out the issue is with failed catalytic converter and they had to replace it. Since then, the acceleration has not been that great and had continuous issues with random engine noises etc

Went By Lee Hyundai of Fayetteville my 2025 Hyundai Santa Fe [XXX] my vehicle gave a warning check transmission oil immediately vehicle was sluggish. I was told to bring it back Monday October 6th they kept it for a week pick it up today October 10th, 2025 they worked on it I had to bring it right back. Went to Sam's club up the street got ready to leave message pops up check your transmission oil immediately call dealer had me to bring it back light stayed on driving there RPM wouldn't get over 2.5 I thought I was going to get run into stopping and going back made there dealership working on it again just purchased it [XXX] little over 3,6004miles I was scared to death INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

We have experienced sluggish/poor acceleration response, scary hesitation at take off regardless of how hard you depress the gas pedal and when driving and are at a speed approx.45-55 mph and press the gas pedal as much 75% and there is no acceleration. I have had the vehicle at an authorized Hyundai Dealer repair shop 3 times and have filed a formal complaint with Hyundai. Hyundai states that this problem ridden transmission is operating as designed but not admitting that the design is badly flawed, to the point where Hyundai have discontinued this transmission in the 2026 version of this vehicle. This is not a complaint based on personal preference or likes, yet it is totally based on the fact that this is drivetrain is very unreliable and unsafe.

Re: 2025 Hyundai Santa Fe VIN: [XXX]   I am facing several issues that require immediate attention. Below are the unresolved concerns: Transmission Problems 1. When driving downhill with the cruise control on, the transmission produces significant vibrations and makes a lot of noise. This is unacceptable and needs to be checked and fixed, as I am very concerned about my safety.   2. When accelerating from speeds above 45 miles per hour, the RPMs exceed 5,000, but the car does not increase in speed. The transmission fails to shift properly. This has happened three times, and it is very dangerous.   3. During hot weather, the car has stalled multiple times when I accelerate. This has put me in dangerous situations when the car stalls in traffic.   Gas Mileage 4. I have observed a significant reduction in fuel efficiency during high-temperature conditions. Specifically, the gas mileage decreases by approximately 20% to 30% when driving home in the afternoon heat compared to my morning commute, even though I follow the same route.     Message sent to Hyundai.com on 7/14/2025 with supporting documents.   On July 12, 2025, I arrived at my scheduled service appointment at Earnhardt Hyundai regarding my 2025 Santa Fe. To ensure a thorough evaluation, I provided the service technician with a detailed list outlining the specific issues I have been experiencing with the vehicle (attached for your review). It is deeply concerning that Earnhardt Hyundai did not document or formally acknowledge all the complaints I submitted to the service department. (attached invoice) This lack of attention is particularly troubling in relation to the persistent issues with the dual-clutch transmission (DCT) 
 INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

I have had issues with my dual-clutch transmission slipping gears in multiple ways while driving; most commonly while in drive and going downhill the tachometer will aggressively rev when just idling and without pressing the accelerator. Also, when trying to reverse out of a parking space on an incline or decline multiple times I have rolled forward as if in neutral and receiving no power to back the vehicle in reverse. Previously owned a 2023 sonata with similar transmission issues and blew a cylinder on the highway within a year of ownership(engine knocked out while driving about 65 and just lost power and had to pull over on side of highway. Went to dealership yesterday for regular maintenance and told them about transmission issues. They checked vehicle for any tcu updates and there were none. Test drove it and said it was driving normal. I know it’s not driving normally/safely. What can I do?