2017 Hyundai Santa Fe problems

“The engine light came on. Upon driving it on the highway it would lost acceleration but was able to drive under 50 miles per hour about 5 miles. When opened the hood there was fluid splattered on the engine. There is a hole in the upper left quadrant beneath the engine cover.”

“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 NHTSA investigate this pattern.”

“Odometer Fraud. The contact purchased a 2017 Hyundai Santa Fe. It was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. At the time of the purchase, the mileage was 45,000. However, when the vehicle was taken to a dealer for a trade-in, it was discovered via a Carfax report that the mileage was over 109,000.”

“Hyundai performed recall #9C2, on 7/2/26. Since that time, the engine has a full time miss. When it is cold, it will hesitate, kick and buck. Hyundai is aware of this. Their solution is to warm the car for 3 to 5 minuets before moving. What happens if there is an emergency and you can't wait? Possible accident with injuries trying to pull into, or cross traffic! I have filed a case with Hyundai, and they just update that they are aware and working on a solution with no expected date for the software fix. This is a serious problem, and they need to fix SOON! Also, when an engine runs like this, over a period of time it will destroy the catalytic converter. Who's going to pay for that??”

“Vehicle was brought to an authorized dealership for service, and while there Campaign 9C2 (ECU Software Update for Theta II Emissions Improvement) was performed. Immediately following this software update, the vehicle developed drivability degradation, specifically engine stutter/hesitation and rough transmission shifting during cold starts. When attempting to accelerate in the first few minutes of driving, the vehicle delays engagement and then suddenly surges or lurches forward unpredictably. This creates a safety hazard, as the unpredictable power delivery and lag prevent the vehicle from accelerating safely when merging into traffic or turning across oncoming lanes, placing occupants at an immediate risk of a collision. The software logic error is fully reproducible every time the vehicle has sat long enough to cool down. The dealership confirmed the update was applied. There were no warning lamps or symptoms prior to the 9C2 update; the failure was caused directly by the manufacturer's campaign software modification to the Engine Control Unit (ECU). The vehicle and its ECU are available for inspection upon request.”

“After performing regular oil changes, and even a new fuel pump sensor, I experienced an issue. Last oil change was within the past two weeks. Driving home from the mountains, I heard a knocking sound from the engine bay. I narrowed it down to all gears above 2500RPM, increasing knocking with RPM speed. I took it easy on the engine, mostly coasting down the mountain. Suddenly during acceleration on an uphill, a pop sounded, and copious white smoke started coming from the engine bay. I pulled over despite having no power brakes but I was fortunate to be near an off ramp in a rural area. Trying to troubleshoot roadside, i noticed fluid on the tie rod, but I wasnt able to determine what kind of fluid it was. When I try to start the car, there is one single click, the engine wont even attempt to turn over. Oil, battery and check engine lights are all on. After towing, I found that the fluid leaking from the vehicle is oil. The vehicle is currently at a transmission shop, but from my research, this isnt a transmission issue but a blown rod bearing the Hyundai engines are know for. I will be contacting a dealership to see if they will at least confirm my diagnosis.”