2017 Hyundai Santa Fe acceleration problems

Filed Sep 9, 2026 · Acceleration, Engine · NE

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.

Filed Aug 21, 2026 · Acceleration, Engine · NC

Directly after the dealer, Johnson Hyundai of Apex, completed Service Campaign 9C2 on 4/28/26, my vehicle began sticking, surging, and harshly changing gears. I have followed up with the dealer multiple times. They said they are not getting back any diagnostic error codes (outside mechanic shop also confirmed they're also not seeing error codes), but went ahead and recalibrated the ECM. They told me to drive for 200 miles and the issue should be resolved. I have now driven 1,500 miles and the issue persists. I'm now seeing Hyundai put out a 'Driveability Communication" about this issue, but there is no proposed fix/recall. This issue did not exist before this service campaign was performed by the dealership.

Filed Jul 27, 2026 · Acceleration, Engine · VA

The 9C2 campaign software update introduced dangerous vehicle hesitation and unpredictable gear changes in active traffic, presenting and immediate crash hazard

Filed Jul 7, 2026 · Acceleration, Engine · AL

Hyundai Campaign 9C2 recall update: Took my vehicle in to have the Hyundai Campaign 9C2 recall update performed on the vehicle on June 9th, 2026. Since the update the vehicle is hesitant/jerky upon first drive of the day or anytime it sits more than a few hours. Occasionally it will do this while I am driving. I feel it is a saftey risk because this could cause my vehicle to abruptly hesitate without braking and cause someone to hit me, or worsetransmission to fail while at highway speeds. I took it back to the dealer that performed the required update around june 23rd 2026 and informed them of the problem caused by the 9C2 campaign update.I got the we don't know anything about it causing problems runaround. Even though it has been documented that dealers were notified of this problem. They then wanted to charge me a $100 diagnostic fee to see if it might be something else, I declined that because I know it is from this update. My vehicle ran perfectly fine and smooth before this update was applied and no CEL lights are on. I did this update because it was required to be done by Hyundai. When I started researching why my vehicle was hesitant/jerky after the update is when I found that anyone that did this update is having these same issues, and it has been happening for a while now and Hyundai corporation has done nothing to correct this problem other than tell us to sit for at least 3 minutes or more before driving it. That does not help when it does it even after driving for a bit and possibly creating transmission problems.

Filed Jul 7, 2026 · Acceleration, Driver assistance · 130,000 miles · TX

The contact owns a 2017 Hyundai Santa Fe. The contact stated that while driving approximately 15 MPH on the interstate, the contact heard an abnormal tumbling sound coming from underneath the vehicle. The contact noticed an unknown object had detached from the vehicle. Upon inspection, the contact determined that the detached component was the radar sensor. The Automatic Emergency Braking (AEB) system and the adaptive cruise control became inoperative. The contact stated that the vehicle had not been involved in a crash prior to the failure. The vehicle was taken to an independent mechanic for inspection. The mechanic advised that the radar sensor could not be reattached and stated the failure was possibly caused by a crash. The local dealer was contacted, but the vehicle was neither diagnosed nor repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 130,000.

Filed May 19, 2026 · Acceleration, Engine · KY

After the installation of the Service Campaign 9C2 engine update, the car now seems to surge or rev up briefly at lower speeds like it can't find the right gear or is trying to briefly accelerate. It doesn't seem to be as noticeable at highway speeds, but in residential or low speeds, it's very noticeable and a little unsettling as the car feels like it wants to briefly lunge forward. No lights are on the dash and there is no indication of any malfunction, but it did not behave this way prior to the 9C2 engine program update. I waited for a couple weeks before contacting Hyundai Corporate about this issue because I was hoping maybe the transmission or engine was relearning after a battery disconnection, but it has not gone away.

Filed Jul 25, 2025 · Acceleration · NJ

Twice my car's gear shifter went from Drive to the right hand side of the gear box. 90% or more of the power cut out immediately creating a massive safety issue. In both instances, i was pulling into traffic after making complete stops at stop signs. The first time, i turned left, the second time I turned right. The shift was untouched by me as it is not a stick shift car. Hyundai charged me close to $400 for the privledge of telling me that I or something bumped the shifter to the right. Also they claim that the shifter is designed to go into low gear if it does go to the right. a low gear should provide more power not cut it out. They refuse to fix the issue, but wanted me to bring it in so they could duplicate a problem that has occurred twice in four months.

Filed Jul 15, 2025 · Acceleration, Driver assistance · FL

The turbocharger failed on my 2017 Hyundai Santa Fe Sport 2.0T. It is still on the vehicle and available for inspection upon request. The turbo failure caused a severe loss of engine power, making acceleration dangerously slow and unpredictable, especially when merging onto highways or passing vehicles. This sudden reduction in power could have caused a rear-end collision or made it impossible to avoid faster-moving traffic. Yes. The failure was confirmed by two independent service centers: Mavis Tires and Brakes, and Tires and Trust in Pensacola, FL. Both observed loss of turbo boost and excessive oil consumption consistent with turbocharger failure. Yes. The vehicle was also inspected by Allen Turner Hyundai in Pensacola, FL. They did not detect the failure during their inspection, but the issue persisted and was documented by the other two shops. The check engine light came on around 118,000–119,000 miles. After that, the turbocharger lost significant power, making the vehicle unable to accelerate normally. At the same time, the engine began consuming oil at an abnormally high rate, requiring frequent top-offs between oil changes. This suggests internal oil seal failure in the turbo or related component issues. These symptoms are consistent with failed turbocharger bearings or seals, oil starvation, or blocked oil lines causing overheating and damage. Such failures can release oil and metal debris into the intake and exhaust systems, risking further engine damage or even fire. Hyundai previously issued a software update (KSDS) to detect early bearing wear in these engines, which my vehicle received in 2019 (Service Campaign 953). Despite this, the turbo failure still occurred, suggesting the underlying design or manufacturing issue may not have been fully resolved. I am requesting that the federal safety agency investigate this pattern of failures, given the safety risks of sudden power loss and potential fire hazard from oil leaks.

Filed Nov 26, 2024 · Acceleration, Engine · SC

The engine seized due to an issue with the oil plug and another part, leading to a lack of oil in the system. The vehicle is currently with Hyundai and available for inspection upon request. How Safety Was Put at Risk: While driving on the highway, I suddenly lost acceleration (below 40mphs). I was forced to pull over to the left side of the highway where it was shallow, where I risked being hit by passing vehicles until there was a safe break in traffic, allowing me to maneuver to an exit. This created a hazardous situation for both myself and other drivers. Reproduction or Confirmation of the Problem: The issue has been confirmed by an independent automotive technician, who diagnosed the problem as a blown engine caused by a lack of oil. The vehicle is now with Hyundai for further inspection. Inspection by Others: The vehicle has been inspected by an independent service center and is currently being inspected by Hyundai. No other parties, such as the police or insurance representatives, have been involved. Warning Lamps or Messages Prior to Failure: The only warning sign prior to the incident was the check engine light blinking at the time of the failure. There were no other warning lamps, messages, or symptoms before the engine seized. The vehicle was within the oil range limit of 7,500 miles at the time of the incident. Additional Notes: The incident occurred suddenly, without prior warning or indication of an issue. Based on the diagnosis and known issues with the oil plug, I believe this failure was caused by a defect.

Filed May 10, 2024 · Acceleration · TX

The traction control system engages too frequently and makes the vehicle unable to accelerate and far too long to disengage, endangering my family during right turns onto lanes with traffic. the traction control system will engage even when there is no loss of traction, only a moderate acceleration with some turn angle. this has caused near accidents about once a month, that both me and my wife experience. there are no active recalls. all recall work was completed last year. this issue has persisted for the length of my ownership, last occuring only about week ago, and about once to 2 times a month.