2017 Hyundai Tucson vehicle speed control problems

“While going down the highway at around 72 mph , my car went into limp mode. I was unable to accelerate, the brake and wheel locked. And then the engine light began flashing. The limp mode , non acceleration, and flashing engine light have happened twice before this instance. The first two times the pulled the P1326 knock sensor code and replaced it. Did the update, and sent me on my way saying it was fine. Now this most recent time (the 3rd time), the engine has failed. A CARFAX report says my car already had the engine replaced at 52k miles, meaning there’s 1 something internally wrong and 2 it’s still well within mileage warranty for another engine replacement. This car is extremely dangerous as it can literally stop in the middle of the highway. I went from 72 to about 15 mph in seconds, I was unable to get over or accelerate. It was terrifying. Now dealing with Hyundai - they don’t want to take fault.”

“The vehicle has experienced life-threatening safety defects during operation; shaking, hesitation, and stalling in high-speed traffic. The vehicle unexpectedly stalled/lost power while driving, putting myself and others in direct risk of collision. The Hyundai dealership claimed it needed an Actuator Gasket replacement, Throttle Body replacement, and ECM/TCM update. The vehicle had NO warning lights until after it stalled, then warning lights illuminated briefly. The Hyundai dealership claimed repairs were "completed" 5/8/26; within 72 hours of "completion" the vehicle's symptoms reappeared. The Hyundai Executive Case Manager has made NO efforts to resolve this LIFE-THREATENING SAFETY issue. This has put myself and children in danger and is legally unsafe to drive.”

“My 2017 Hyundai Tucson is experiencing dangerous, sudden engine stalling, which are symptoms directly matching Service Campaign T1B. These critical safety issues surfaced following a total engine replacement in June 2025. Despite the vehicle being within the 12-month/12,000 mile workmanship warranty, the dealership is refusing to honor this coverage or offer goodwill assistance. My claim is based on a documented pattern of physical and technical negligence: - Failure to Update Software: The dealership failed to perform the mandatory ECM/TCM software integration (Campaign T1B) during engine swap, which is required to prevent the exact stalling I am now experiencing. - Dismissal of Warning Lights (Code P0456): One day after the engine replacement was “completed,” I returned to the dealership because the Check Engine Light illuminated with Code P0456. This was dismissed by the service provider without a proper diagnostic resolution, despite being a direct indicator of improper vacuum line reconnection during the engine installation. - Mechanical Negligence (Coolant Leak): Post-engine swap, the vehicle developed a coolant leak, which was a direct result of improper…”

“severe oil consumption. the vehicle eats the oil at an alarming rate. having to fill the oil tank very often and the engine light has been on. it is affecting acceleration at 30mph where the engine warning light will flash. It also completely dies while driving. very unsafe and needs to be resolved.”

“Issue was first noticed in October 2025 - there are roughly 70k miles on the vehicle. It is a 2017 vehicle, and has regular service (oil, inspection). There was a class action lawsuit for this issue (wylie v hyundai), which was settled prior to the purchase of the vehicle. Vehicle stutters when shifting into and out of first gear. A local mechanic and hyundai both confirmed that it was a transmission defect. The Hyundai dealership initially thought it was an actuator issue, but has since said that it is a faulty gear assembly. it has a DCT (dual clutch transmission). Vehicle suddenly stops and is erratic when driving. Coming out of a stop risks the vehicle shuddering; going through an intersection or turning cross traffic is extremely dangerous as the vehicle could stop momentarily and cause a collision. Vehicle is unable to maintain flow of traffic. The problem appears to be widespread - there are various forums we found where others have this same issue. There were no warnings on the dashboard prior to the issue. When issue appeared a check engine light was displayed.”

“- Kept regular 5K-6K oil changes since 2022 when I purchased the vehicle -Took the vehicle to a Hyundai dealership, multiple times, to ask about the engine stalling at a stop or slow turn, and/or jerking. -July '25 new oil change and flushed engine -October'25- no engine or oil lights. Engine seized and needs to be replaced. - VIN didn't populate recall but the symptoms are the same”