2021 Hyundai Tucson: sudden loss of power

Filed Oct 10, 2026 · Acceleration, Electrical · NV

loss of info system loss of all dash lights when I turn the engine off most of the time I loose all electrical systems (will not start for at least 15 minutes) if doors lock I can only unlock the drivers door with the auxiliary key. Has tried to shift in to park while driving (one time) Lost all power (engine and steering while crossing a highway (once only)

Filed May 4, 2026 · Engine · NJ

My 2021 Hyundai Tucson has experienced repeated engine-related failures associated with a knock sensor (P1326) fault that causes the vehicle to enter limp mode and lose power while driving. This issue has occurred multiple times at approximately 15,000, 17,000, 41,000, and 90,000 miles and has resulted in four separate incidents requiring towing. During these events, the vehicle suddenly loses power and cannot maintain normal driving speed, creating a hazardous condition while in traffic. The vehicle has undergone multiple repair attempts, including an ECM update and three knock sensor replacements. Despite these repairs, the issue continues to recur and no root cause has been identified. Hyundai has not provided a permanent fix and has advised continued operation of the vehicle unless the issue occurs again. This ongoing condition presents a safety concern due to the risk of sudden loss of power while driving.

Filed Mar 13, 2026 · Engine · CA

While driving on the freeway, my 2021 Hyundai Tucson SE (72,021 miles) suddenly and without warning lost power and entered limp mode. I was able to safely maneuver to the shoulder and exit the freeway. The check engine light came on and is currently flashing. I took the vehicle to AutoZone where code P1326 was retrieved. I then took it to Pep Boys for a full diagnostic where P1326 was the only code present. The Pep Boys report states the vehicle requires immediate attention. The vehicle remains in limp mode and the check engine light is flashing. The vehicle is not being driven as it cannot safely reach freeway speeds. I contacted Hyundai Customer Care and was assigned Case # XXX. I also contacted a Hyundai dealership who attempted to charge a $225 diagnostic fee despite P1326 being a known Hyundai defect covered under recall/service campaign. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 9, 2026 · Engine, Fuel system · SC

The vehicle experienced a catalytic converter efficiency failure that was confirmed by an authorized dealership in January 2025. The dealer indicated the catalytic converter required replacement; however, the replacement was not performed, and the vehicle was returned to service with an unresolved emissions defect. Less than one year later, the vehicle developed recurring emissions system failure, loss of power, drivability issues, and repeated warning indicators. The vehicle is currently out of service while additional components, including oxygen sensors and spark plugs, are reported to be affected. The manufacturer is declining to replace the catalytic converter and is attributing the condition to oil consumption despite the prior unresolved emissions failure. The issue has been confirmed by dealership diagnostics and has resulted in prolonged loss of use of the vehicle. This appears to be a continuing engine and exhaust/emissions system defect that was not properly remedied when first identified and may affect safe operation of the vehicle.

Filed Nov 4, 2025 · Engine · FL

Engine started making a knocking sound, then the oil light came on followed by the check engine light. Accelerates and decelerates on its own. Was forced to immediately pull over across three lanes on Interstate 95. It’s been over two weeks and I’ve yet to hear if Hyundai is going to cover a replacement engine. However, what happened is exactly what they have listed on their website ⬇️ What to look out for check-engine Check Engine oil-light Engine Oil Pressure A knocking noise from the engine that increases in frequency as the engine rpm increases. Reduced power and/or hesitation and vibration. Illumination of the “check engine” light in the instrument cluster. Illumination of the “engine oil pressure” warning lamp.

Filed Nov 3, 2025 · Engine · TX

My family’s safety is at serious risk with my 2021 Hyundai Tucson, which I’ve owned only 55 days. This vehicle has stalled three times while driving, putting me and my two young children in immediate danger. Each time, the car operated normally until a flashing engine light appeared, RPMs spiked, and the vehicle suddenly lost all power—entering “limp mode” and unable to exceed 3,000 RPM or 50 MPH. The first failure occurred 9/14/25 while merging onto the interstate, forcing me to lose power mid-acceleration as surrounding vehicles slammed their brakes to avoid collision. 13 days later, it happened again in stop-and-go traffic, leaving me stranded on the shoulder. Both incidents occurred without warning or prior check-engine lights. The third—and most terrifying—incident was on October 17, 2025, when the engine completely died 300 miles from home on a busy highway. My children, ages 4 and 6, were terrified as cars sped by. We were extremely fortunate not to have been hit. I am urgently requesting assistance for the immediate replacement of this vehicle’s engine. It is covered by Hyundai’s 15-year/150,000-mile extended warranty, clear evidence the company was aware of these issues. Service records from the previous owner-that I was told about by Hyundai show ongoing engine problems and recalls since 2022 further proof this vehicle should have been retired from service As a parent, I’m very alarmed that Hyundai refuses to act until “catastrophic damage” occurs. This policy is irresponsible and endangers entire families. There’s at least 50 the federal safety agency complaints describing identical issues; stalling, power loss, and bearing failure linked to defective connecting rod bearings. Yet, Hyundai has denied a replacement, insisting on waiting for further damage and failures in operation. I beg you to intervene and prioritize my family’s safety before tragedy inevitably strikes. My children should not be put at risk due to corporate negligence, greed and absence of accountability.

Filed Feb 22, 2025 · Driver assistance, Electrical · NE

Vehicle has 36,300 miles. Engine stalled twice when shifting into reverse, MID displayed "BCW On, Check System." Continued driving home, vehicle experiences power loss (rpms drop to ~500) and electrical system sputters and sparking noises can be heard in the cabin momentarily when turning left or steering left for curves at speeds over ~20mph. Checked BCW sensor location in rear bumper for obstructions - vehicle is clean.

Filed Jun 19, 2023 · Driver assistance, Electrical · CA

I've had numerous issues with my vehicle, including power steering, brakes, loss of power, and more. On a few occasions, I started my vehicle and put it into drive, only to find that the power steering hadn't disengaged. This led to near collisions, such as almost hitting another vehicle while backing out of a parking spot and nearly running into a wall. I've reported these issues to Hyundai multiple times, but the dealership can't reproduce the problem, despite having recordings of the incidents. I've also experienced delayed release of the electronic e-brake and it feeling like it hadn't fully disengaged. In a recent event, with passengers in the car, the e-brake auto-engaged while driving downhill, bringing the vehicle to a halt. I had to manually disengage it and restart the vehicle to resume normal operation. I contacted Hyundai customer service again, but I'm still waiting for a formal response. Other symptoms include loss of power during acceleration, engine starting issues, stuttering, and occasional burning smell from the brakes. Despite my efforts, Hyundai hasn't provided any solutions to these problems. I drive with multiple passengers in my vehicle all the time, including children and have major concerns regarding any of these issues happening, let alone while I am driving at higher speeds or with someone else driving my vehicle.

Filed Mar 31, 2023 · Engine · ME

March of 2021 I purchased a new Hyundai Tucson SEL. I have performed all required maintenance (at the dealer no less). In May of 2022 the dealer performed the recall Campaign 966. Since that time, my Tucson has had to go to the dealer 5 times for a P1326 code. This resulted in the check engine light flashing and the car going into protection or limp mode. The vehicle would not accelerate past 30 mph and would not exceed 2000 RPM. This has happened as I have accelerated from either a stop or while in traffic. As of yet the dealer has been unable to permanently resolve the problem. They have replaced the knock sensor. The dealer has replaced spark plugs. The dealer has also replaced the catalytic convertor. They also recently scoped the cylinders and cleaned the engine with pressurized engine detergent. In the days and weeks prior to the check engine light, I can always tell that failure is imminent. The gas mileage will slowly drop off during both highway and city driving. Additionally, I can feel through the gas pedal hesitations and slight rhythmic pulsing. Lastly, I can feel gradual power loss in acceleration and very slight hesitations in acceleration as well.