Hyundai Santa Fe loss of power problems

Filed Nov 5, 2026 · Engine · TX

I am submitting a complaint regarding engine oil consumption in my 2017 Hyundai Santa Fe Sport 2.4L 4-cylinder with approximately 117,000 miles. The vehicle consumes approximately one quart of engine oil every 5,000 miles during normal operation. There are no visible oil leaks or noticeable exhaust smoke. I am concerned that the engine may be consuming oil internally due to a possible defect involving the piston rings, valve seals, or another internal engine component. The exact cause has not been professionally diagnosed. Excessive oil consumption creates a safety concern because low engine oil levels can lead to inadequate lubrication, sudden engine failure, or loss of engine power while driving, potentially putting the driver and other motorists at risk. The condition has not yet been formally confirmed by a dealership or independent repair facility. The vehicle has not undergone a formal manufacturer or third-party inspection specifically for this issue. The engine is available for inspection upon request. There are currently no check-engine warning lights or diagnostic trouble codes. No visible smoke or external oil leaks have been observed. The primary symptom is the gradual loss of engine oil during normal driving. I am requesting that the federal safety agency document and investigate this condition to determine whether it may be related to an engine defect affecting Hyundai vehicles equipped with the 2.4L engine.

Filed Nov 2, 2026 · Engine · NY · crash

Supplement to complaint 11743619. The 3.3L Lambda II GDI engine seized at highway speed on January 16, 2022 (connecting-rod-bearing failure, internal components through the block). The vehicle lost all power and power steering, left the roadway and crashed off-road while the driver tried to bring it to a stop, with four occupants aboard. Hyundai's TXX8 warranty extension covers engine repair or replacement for 15 years/150,000 miles and states eligibility is determined upon an inspection of the engine. Hyundai Motor America (Case #42605065) has refused to inspect the engine, citing rodent-related damage and outside influence. The engine has not been inspected under TXX8 and the failure cause has not been determined. Photographs of the block and the debris-torn front harness are available on request.

Filed Nov 1, 2026 · Engine, Fuel system · NJ

For approximately the past year, my 2021 Hyundai Santa Fe, currently with about 23,000 miles, has experienced intermittent engine and fuel-system problems. During start-up, the vehicle sometimes makes an abnormal rattling/cranking noise, followed by noticeable engine and vehicle vibration. Warning lights may appear, and on some occasions the engine does not start successfully on the first attempt. When it does start, it may initially run rough. The vehicle has also stalled intermittently and has had repeated incidents where pressing the accelerator produced little to no engine response or acceleration. This creates a serious safety concern because the vehicle may unexpectedly stall, lose power, or fail to accelerate when needed while driving. The vehicle has been at an authorized Hyundai dealership for more than one month. The dealership has been working with Hyundai Tech Line and has replaced or evaluated the low-pressure fuel pump, high-pressure fuel injector, high-pressure fuel pump, MPI/port fuel injector, and valve cover. The latest recommendation is to drain, clean, and refill the fuel tank. Despite these repair attempts, the root cause has not been clearly identified or permanently resolved. I am concerned that the repair process has become trial and error, with additional components being replaced while the underlying safety-related issue remains unresolved. I am also being asked to pay out-of-pocket for some of these unsuccessful repair attempts. The vehicle is currently at the Hyundai dealership and is available for inspection if needed.

Filed Oct 15, 2026 · Electrical, Engine · CA

On [XXX], Laguna Niguel Hyundai performed Service Campaign 9C2 (ECU software update for Theta II emissions improvement, Hyundai TSB 26-01-013H) on my 2017 Hyundai Santa Fe Sport. Immediately after the update, the vehicle developed drivability problems that did not exist before: rough/harsh shifting, hesitation, and loss of power during cold-start operation (the first 1-3 minutes after engine start), plus intermittent infotainment and navigation system failures. Hyundai's own dealer notice dated 05/18/2026 acknowledges vehicles may exhibit 'hesitation or rough shifting' after the 9C2 update and states the matter is 'currently under review' — no permanent fix has been released. The dealership that performed the recall has since refused to service my vehicle again. I opened case #[XXX] with Hyundai corporate; my inquiries on 09/03/2026, 09/11/2026, and 09/17/2026 asking for a corrective action have gone unanswered. The hesitation and power loss are a safety hazard when merging into traffic or crossing intersections. I request the federal safety agency investigate this pattern. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 13, 2026 · CA

On XXX, [XXX] Hyundai performed Service Campaign 9C2 (ECU software update for Theta II emissions improvement, Hyundai TSB 26-01-013H) on my 2017 Hyundai Santa Fe Sport. Immediately after the update, the vehicle developed drivability problems that did not exist before: rough/harsh shifting, hesitation, and loss of power during cold-start operation (the first 1-3 minutes after engine start), plus intermittent infotainment and navigation system failures. Hyundai's own dealer notice dated XXX acknowledges vehicles may exhibit 'hesitation or rough shifting' after the 9C2 update and states the matter is 'currently under review' — no permanent fix has been released. The dealership that performed the recall has since refused to service my vehicle again. I opened case #XXX with Hyundai corporate; my inquiries on XXX asking for a corrective action have gone unanswered. The hesitation and power loss are a safety hazard when merging into traffic or crossing intersections. I request the federal safety agency investigate this pattern. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 5, 2026 · Transmission · CT

My 2023 Hyundai Santa Fe Calligraphy has experienced transmission problems since it was new and currently has approximately 20,000 miles. I brought it to the dealership approximately three to four times for these concerns, but I was told they could not find a problem or any diagnostic codes. Recently, while driving on the highway, the vehicle lost power and would not accelerate even with the accelerator pedal pressed all the way down. I had to pull over to the side of the highway. Without turning off the engine, I shifted into Park and then back into Drive. The vehicle began moving again, but the transmission continued slipping. On [XXX] I brought the vehicle to Key Hyundai of Manchester for scheduled maintenance and again reported the recurring transmission problems. The dealership requested a diagnostic fee of more than $200, which I declined because I had repeatedly reported this problem since the vehicle was new. They completed the scheduled maintenance without performing the requested transmission diagnosis. After leaving the dealership that same day, the vehicle repeatedly malfunctioned while I was driving, and the check engine light came on. I returned to the dealership. A scan showed three fault codes related to the transmission, clutch, and a sensor. I asked to leave the vehicle and receive a loaner because I feared another loss of power on the highway could cause a rear-end collision. I was told the person who could authorize a loaner had left for an appointment, could not be contacted, and that I should return Monday. On [XXX], I called and spoke with Anthony, whom I was told was in charge. He told me I needed to bring the vehicle in and would have to join a waiting list for a loaner. On [XXX], I brought the vehicle back, and it is currently at the dealership being evaluated. My primary concern is safety: recurring transmission slipping and a loss of acceleration that left me unable to maintain speed on the highway. IINFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C

Filed Sep 27, 2026 · Engine, Transmission · MD

Immediately following the mandatory Hyundai Servie Campaign Update 9C2-ECU THETA 11my vehicle began exhibiting severe hesitation, very rough idling, jerking at slow speeds and when gear changes, difficulty going up inclines and almost feel at times as though it is about to lose power which poses life threatening situations especially when turning into traffic. I have reported it to the dealers who never once test drove the vehicle but said to me that they did and could find no problem, however they did make me pay for repairs which never fixed the problem. I returned three times with the same issue. They recommended a Fuel Induction Service and a Auto Trans Service. Spark plug change. Igniton coils change. Nothing worked!

Filed Sep 20, 2026 · Engine, Transmission · OH

Component/System Failed: Engine assembly (Theta II 2.4L GDI) and Exhaust/Catalytic Converter. Description: The vehicle suffered a failure associated with the known Theta II engine defects. Engine oil consumption and internal engine wear directly led to unburned fuel and debris entering the exhaust stream, resulting in severe catalytic converter restriction/failure. Safety Risk: The combined failure caused sudden loss of power while driving, engine stalling, and significant driveability hazards, creating an immediate risk of a rear-end collision on public roads. Confirmation & Inspection: The failure was confirmed and diagnosed by a certified service facility. Replaced components and diagnostic documentation remain available for inspection upon request.

Filed Sep 10, 2026 · Engine · IL

At approximately 122,000 miles, my 2020 Hyundai Santa Fe experienced a serious engine malfunction while I was driving on the highway. The check engine light suddenly illuminated and the vehicle began thrusting/jerking forward unexpectedly. We immediately took action to exit the highway and were able to get off the highway, but the engine died before we could fully stop the vehicle. This created a serious safety risk because the unexpected jerking and subsequent loss of engine power occurred while traveling at highway speeds and could have resulted in loss of control or a collision. The vehicle was towed to a local independent mechanic. After inspecting it, the mechanic stated that the engine needed to be replaced and recommended taking it to a Hyundai dealership because of the continuing issues associated with the Theta II engine. The vehicle was then towed to the Hyundai dealership. The Hyundai dealership inspected the vehicle and determined that cylinders 2 and 4 were not firing and recommended replacing the valve shaft. We requested a complete engine replacement. Hyundai initially offered a 50/50 split of the repair cost, but after we requested an engine replacement, Hyundai declined and instead offered a 70/30 cost split. There was also a previous documented concern regarding increased oil consumption, as noted in an earlier oil-consumption report. The vehicle has been inspected by both an independent mechanic and a Hyundai dealership. The vehicle and engine components are available for inspection upon request. No police or insurance inspection was performed, to my knowledge.

Filed Sep 10, 2026 · Transmission · ME

Our vehicle does this all the time and has done so for almost two years. After starting the vehicle and then shifting to a gear, either drive or reverse. The vehicle does not always go into gear. When you take your foot off the brake to push on the accelerator, the vehicle will start to roll in the opposite direction if you are on a very small incline in the opposite direction. If you are on flat ground, the car will not move for a few seconds. If the incline is in the direction of your selected gear, you start rolling in that direction with no power from the transmission. In one to three seconds you get power to the transmission. This happens at any time of the day, from the very first start up, to anytime during the day when in use. If you stop to get gas and when you restart the vehicle it can happen. We have almost hit other cars and people several times from rolling backwards when we have drive selected because the transmission does not properly engage. Everytime it happens I say to the car, why are you doing this? The only reason we haven't hit anyone or another car is because I hit the brakes again very quickly once we start rolling backwards after we do not start going forward. Not sure if it is associated or not, but driving through the parking lot a few times in drive. We have lost all power to the transmission. You are driving along and without any visual indications or sounds, you just start slowing down. If you press on the gas more, it does nothing to increase the speed of the vehicle. It has only happened once to us on a road going 45 mph. The power came back after a few seconds.