2021 Hyundai Tucson: stuck in gear or won't shift

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 Jan 22, 2026 · Engine · 28,944 miles · PA

The contact owned a 2021 Hyundai Tucson. The contact stated that immediately after purchasing the certified vehicle, the vehicle went into LIMP Mode while her grandson was driving approximately 65 MPH, and the vehicle decelerated to 7 MPH. The vehicle was towed to the local dealer who diagnosed that the NOX sensor had failed and needed to be replaced. The vehicle was repaired but while leaving the dealer, the failure reoccurred. The vehicle was towed back to the dealer who replaced a second NOX sensor and the catalytic converter. The contact stated that days after retrieving the vehicle, the failure reoccurred, and the vehicle was towed back to the dealer who diagnosed that the NOX sensor had failed for a third time, within several days of owning the vehicle. The vehicle was traded in. The manufacturer was notified of the failure. The failure mileage was 28,944.

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 Sep 13, 2025 · Acceleration, Engine · CA

While driving on a major highway, my car went into limp mode topping out at 60 mph then decreasing before going back to 60. My check engine light was also blinking, not solid.

Filed Jul 15, 2025 · Engine · NC

There was a recall on this engine which I had updated the knock sensor campaign. While on the highway the engine light started flashing and the speed was reduced to 20 mph on a major highway. I had to almost cause a wreck to get off highway. The vehicle went into limp mode with no prior indication

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.

Filed Feb 6, 2023 · Electrical, Engine · KS

Check engine light comes on flashing for a knock sensor. This has happened four times. Since it is flashing, car goes into limp mode and won’t go over 2000 rpm, low speeds and slow/no acceleration. It is dangerous due to happening on highways and going from cruising speeds to a crawl, with minimal ability to accelerate, very quickly. Sensor has been updated once and sensor has been replaced twice. Currently dealing with corporate after the fourth time of this issue happening. I am still fighting this issue and it’s looking like I will need an attorney.