2025 Hyundai Santa Fe Hybrid

Vehicle experienced a loss of acceleration while driving. When pressing the accelerator, engine RPM increased significantly but the vehicle did not increase speed. The vehicle felt as though it was stuck in one gear and would not upshift or downshift. The issue was most noticeable while driving uphill, where the vehicle was unable to maintain speed despite full throttle input. This created a safety concern as the vehicle could not accelerate normally in traffic conditions. The problem has been progressively worsening over time. Initially there were mild symptoms, but it has become more severe and frequent, culminating in a near-complete inability to accelerate under load. No warning lights or messages were observed prior to or during the failure (if that’s true—adjust if needed). Vehicle has approximately 28,000 miles. The vehicle is currently at a dealership for inspection and diagnosis, but the issue has not yet been confirmed or resolved at the time of this report.

While driving at highway speeds (59–75 mph), the vehicle suddenly lost propulsion power and entered a reduced-speed “limp mode,” rapidly decelerating and creating a dangerous traffic situation. The dashboard displayed a “Hybrid Power Control Unit” warning along with audible alarms. During the second incident, the vehicle failed to shut off when the engine stop button was pressed. Multiple adult witnesses were in the vehicle on each dangerous traffic situation.

I was stopped at a red light. When the light turned green, I proceeded to apply the gas and accelerate. I quickly noticed that the vehicle began accelerating at a faster rate than I was intending. The vehicle continued to accelerate without me applying my foot to the gas pedal. Nothing would stop the continued acceleration (application of brake). I crashed into the rear of a vehicle in my lane going approximately 50-60mph (estimate). I am unsure what the issue was that resulted in this crash. In doing some internet searching, it seems it could have something to do with the transition from electric to gas when I was stopped temporarily at the intersection. It could have been a faulty sensor (throttle position) or software glitch. These components have not been inspected by the manufacturer, police, or insurance representatives. There were no warning lamps, messages or other symptoms of the problem prior to the failure. The crash resulted in the airbags being deployed, I was taken to the hospital with a likely concussion and moderate injuries to my chest and hand. The vehicle that I rear ended was a [XXX] woman with a [XXX] old in the vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Description of the Problem: I own a 2025 Hyundai Santa Fe Hybrid Limited with approximately 3 months of use. While driving on highway, the vehicle suddenly stalled displaying “Hybrid System Failure-Stop by side”. I had to stop on shoulder and restart, drove it couple of days and it happened again. Engine would not start, leaving the vehicle stuck in EV mode only with no ability to accelerate properly, Vehicle wouldnt go beyond 35mph. The vehicle then stalled and became unsafe to operate on a public road. After restarting, the vehicle displayed a Check Engine Light. Tookk it to the dealer and the dealer reported DTC P1122000, but did not provide clear evidence of an internal system fault. The dealer claimed the event was caused by “20% ethanol in the fuel,” which is inconsistent with U.S. pump labeling laws. When I checked my credit card entries around the time for refuel, all of them are reputed gas stations with nothing lower than "87" gas which is in alignment with car manufacturer's recommendation. This sudden stall created a serious safety hazard, and I am concerned this may be a broader issue with the 2025 Hyundai Santa Fe Hybrid drivetrain, fuel system sensors, or hybrid control module. I am requesting NHTSA to look into whether similar complaints exist, as this failure mode can result in loss of propulsion at speed, putting occupants at risk.

My 2025 Hyundai Santa Fe Hybrid has experienced repeated, dangerously abrupt power loss while driving at highway speeds, causing the vehicle to go into "limp mode" without any warning or prior indication. This safety hazard occurred on three separate occasions: First Incident: 7/29/25; Mileage: 9,205. Situation: While traveling at 70 MPH on the interstate, the vehicle suddenly decelerated to 35 MPH and entered "limp mode" without any warning lights or notifications. Dealer Repair: Replaced ignition coil assembly (Parts: 27301R1H, 27301-2M417). Second Incident: 8/27/25; Mileage: 12,898 Situation: While accelerating to 65 MPH on the interstate, the same loss of power and abrupt forced deceleration occurred, again with no warning. This sudden loss of speed created a serious safety hazard for me and other drivers. Dealer Repair: Replaced fuel pump & O Ring Assy-High Pressure (Parts: 35326-2M500, 35305-2m414 LH). Third Incident: 9/25/25; Mileage: 14,830. Situation: Traveling at 70 MPH on the interstate, the car abruptly decelerated, again entering limp mode. This caused surrounding vehicles to swerve to avoid rear-ending me, putting myself and others at risk. Dealer Repair: Replaced High Pressure Sensor (3534202M400), Packing Fuel Pump (31115-0W000), and Fuel Pump and Tube Assy (31119-L1400). In all three cases, there was never any warning light, check engine notification, or app alert before the incident. Hyundai and my dealership confirmed and replicated the issue during each repair. I have reported the vehicle to the Texas DMV, Hyundai and the dealer.These recurring “limp mode” incidents have repeatedly jeopardized my safety, my family’s safety, and the safety of the public due to the sudden, unanticipated loss of power at high speeds. Since the underlying issue persists and has required three separate major repairs, I am fearful for my safety while operating this vehicle and believe it constitutes a serious safety defect needing federal investigation.

Stopped for gas, vehicle started but would not go into gear, engine lights indicated 'Check hybrid system', warning lights shown. 1/2 hr on the phone with dealership to assist. No problem detected when returning to home dealer. Second episode occurred, vehicle at dealer for the past 4 weeks. Episode repeated at dealership yet "no abnormalities are detected with diagnostics ".

I was on a semi residential-commercial street that turns on to a freeway entrance. I was turning right and unavoidably entered the freeway when the sudden loss of power occurred. The car slowed down to about 20 mph and pressing on the gas medal didn't yield any more power. I immediately pulled over to the emergency lane upon entering freeway to let fast moving vehicles pass me on the left side. I turned off the vehicle and turned it back on. It seemed to turn on as normal so I proceeded to drive home slowly, staying on the slow right lane of the freeway driving under the speed limit until I took my exit to get to my home. All seemed ok until I turned onto residential street near my home. Again the car slowed down suddenly to 20mph and giving it more gas did not make a difference. The time difference between the first and second (recorded) incident was 25 minutes apart, having driven the vehicle only 140 total miles. The dashboard flashed a 20mph speed limit even though I never set those parameters, didn't set cruise control, and I didn't have auto stop or hold buttons engaged. The car simply slowed down to a 20mph speed limit without my input to the vehicle settings.

Hi Hyundai- my 2025 Santa Fe calligraphy HEV, with around 900 miles wasn’t turning on and only able to start with a jump. After parking, it was unable to maintain a charge to start up again even after driving 1-2 hours. The dealer wasn’t sure why, replaced the 12v battery first and recharged it overnight. Unfortunately it also drained. Finally diagnosed that the hybrid starter generator needed replacing. More bad news, after replacing they discovered what the service manager said was a defective relay pack of some sort had fused. And the kicker is the part is unavailable until January. I am not sure how widespread or rampant this issue is, but I am concerned there might be more or further issues identified.