2020 Hyundai Santa Fe: sudden loss of power

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 Apr 20, 2026 · Engine · MI

The vehicle (2020 Hyundai Santa Fe, 2.0T, ~88,500 miles) experienced a sudden engine failure with no warning signs—no oil light, knocking, or overheating. After sitting overnight, the vehicle would not start and was later diagnosed by an independent repair facility as having a seized engine requiring replacement. The failure was unexpected and creates a potential safety risk, as it could have resulted in a loss of power while driving. The manufacturer has been notified but denied warranty assistance due to lack of maintenance documentation. The vehicle is currently available for inspection.

Filed Apr 16, 2026 · Engine · TX

Around Feb 15, 2026, at ~85,000 miles, the oil pressure warning light began illuminating at idle and extinguishing above idle speed. The vehicle had also been experiencing intermittent hard starts and occasional shuddering at idle — symptoms too subtle for a typical owner to connect to imminent engine failure. An independent mechanic performed a manual oil pressure test: 4 PSI (Hyundai minimum spec is 13 PSI). The authorized dealer confirmed 6 PSI and found metal shavings in the oil pan — the signature of connecting rod bearing wear documented in Theta II GDI engine failures. Dealer recommended full engine replacement ($8,500). Vehicle has been inoperable at the dealer since Feb 19, 2026. SAFETY CONCERN: At 4 PSI with metal debris in the oil system, this engine was at imminent risk of catastrophic seizure. I avoided highway driving after the warning appeared (max 50 mph, city streets only). Had the engine seized at highway speed, loss of power steering and brake vacuum assist would have created serious crash risk. The symptom profile — warning only at idle, clearing at speed, no knocking, no check engine light — is the pattern that puts less-vigilant drivers at risk of seizure at highway speed with no warning. KNOWN DEFECT: The 2.4L G4KJ Theta II GDI is identical to the engine subject to a $210M the federal safety agency civil penalty (2020), multiple recalls, and a ~$1.3B class action settlement extending lifetime warranties through MY 2019. The 2020 uses the same engine but was excluded. My failure mode is textbook Theta II. Hyundai Service Campaign 9C2 (ECU update for 2019-2020 Theta II, issued Nov 2025) was incomplete on this vehicle — I was never notified. Completed after the engine had already failed. Manufacturer denied coverage (Case #XXX). BBB AUTO LINE claim #XXX filed Apr 16, 2026. No crash. No injuries. No fire. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 6, 2026 · Brakes, Engine · PA

While driving, the engine catastrophically failed without warning, causing an immediate loss of power-assisted braking and steering. The failure occurred while traveling downhill. I was unable to slow or control the vehicle properly and was forced to proceed through a school bus’s flashing lights to avoid a potentially catastrophic collision, resulting in a traffic citation. My son was in the vehicle at the time. A sudden loss of engine power, braking assist, and steering assist while driving presents a serious safety defect. Vehicle was towed to Fred Beans Hyundai in Doylestown where it has been confirmed engine failure. This failure happened immediately and without warning.

Filed Nov 13, 2025 · Engine, Fuel system · 72,700 miles · NY

The contact owns a 2020 Hyundai Santa Fe. The contact stated that while driving approximately 40 MPH, the vehicle started shaking and lost power. The check engine warning light was illuminated. The vehicle was restarted immediately. The vehicle was taken to a dealer, where it was diagnosed and determined that the engine had an air leak with the fuel. The contact added that the leak was stopped after an undisclosed repair, but the failure reoccurred a day later. The vehicle was taken to the same dealer however, the failure could not be duplicated. The vehicle was then taken to the same dealer and was diagnosed and determined that the throttle body needed to be replaced. The vehicle was repaired, but the failure reoccurred two days later. The manufacturer was notified of the failure. The failure mileage was approximately 72,700.

Filed Jul 19, 2024 · Brakes, Engine · NY

While driving on the highway loss of power and all the light on the info area lit up had to pull over on shoulder and shut off car and restart. And on two separate occasion while on low speed local road brake pedal locked up and I could not stop the car using the brake it was like it was press down already and I was unable to stop.