2017 Hyundai Santa Fe Sport: hesitation when accelerating

Filed Oct 14, 2026 · Engine, Transmission · OK

This is in reference to the Hyundai 9C2 ECU software update for Theta II engines that have caused my 2017 Santa Fe Sport to hesitate, surge and run poorly the first few minutes after a cold start! I contacted my dealership but they have not offered any resolution as of yet even though Hyundai Corporate is well aware of the problems caused by the 9C2 software upgrade!

Filed Oct 1, 2026 · Acceleration, Electrical · MN

harsh engagement or hesitation between gears 1 through 3 specifically during cold starts before the powertrain warms up. But also during driving in the highway.

Filed Sep 29, 2026 · Engine · IA

Service Campaigh 9C2 Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. My 2017 Hyundai Santa Fe sport has severe loss of power and rough jerky transmission after the update. This condition will definately cause unsafe driving and vehicle engine and transmission damage. Hyundai corporate and local dealerships indicate no remedy for this situation. Dealer also indicated that Hyundai corporate may not release a new software update to fix the issue. This is unacceptable.

Filed Sep 17, 2026 · Acceleration, Engine · NC

Campaign /Service Update 9C2 / TSB-25-01-087H broke my Hyundai. The car hesitates idling and on acceleration. Hyundai have no solution to this failed software update or acknowledging other issues it may be causing.

Filed Sep 14, 2026 · Acceleration, Engine · LA

I took my SUV to get the 9C2 recall on 8/7/2026 performed and took it home. The next morning when I cranked it and left my driveway it acted as if the vehicle didn't recognize that I was pressing my accelerator. It sputtered and hesitated acceleration for about five minutes. It also acted as if it was not going to change from first to second gear. After about five min. of playing with the gas pedal it straightened out. Twice I was almost hit by other cars expecting me to pull away from a stop sign. I took it back the next day telling the service agent what was happening and he kept it overnight. I received a text saying the technician was unable to find a cold start problem and it was ready to pick up. I was so mad I could barely hold my temper. I took it home and for the next week every single day it acted like this when cold started in the morning. I took it back to Premiere Hyundai of Harvey and was treated rudely this time. They acted as if they never had a single other complaint and told me I might have to leave it for several days so they could cold start test it for several days. This was on a Wednesday morning 8/19. I was never updated or called and when I texted my service rep on Monday 8/24 I was told the tech was not able to duplicate the complaint and to come pick it up. I will not ever buy another Hyundai because of the way I was treated and lied to. PLEASE create a recall for this badly handled recall 9C2. My Sante Fe Sport ran beautifully before this recall messed up my SUV. Now I have found if I let it idle for five minutes in the morning and accelerate slowly until it changes gears, most mornings it will run well, but if I crank it and pull into the street on a cold start it does the sputtering HELP US HYUNDAI OWNERS

Filed Aug 10, 2026 · Electrical, Engine · MN

In June 2026 I took my vehicle to Hyundai for a recall to the ECM module. After that my vehicle would lose power and hesitate to shift gears, and overall does not feel safe. Took vehicle back to dealer and they have told me that I have to wait for them to issue a recall fix for this now .

Filed Jul 23, 2026 · Engine · NY

After a recall repair (Campaign 9C2) was performed on my vehicle, it developed a hesitation and lack of acceleration issue that did not exist before the repair. The vehicle exhibits rough or delayed gear shifting, a noticeable lack of power/acceleration, and behavior that feels like the engine is not receiving adequate fuel. This occurs both during cold start and after the vehicle has been driven and is fully warm

Filed Jul 22, 2026 · Engine, Fuel system · TX

We have a 2017 Hyundai Santa Fe Sport with a refurbished engine due to a past class act settlement, we were notified by Hyundai to bring in the vehicle for Service campaign 9C2 to update the Engine Control Module (ECM) Software for vehicles equipped with the (2.4 GDI) Theta II refurbished engine, which we have. The morning after we updated the 9C2 software, after starting our car cold for the first time in the am, our car went into limp mode, shaking very badly, it would not accelerate above 20 MPH, it had a lot of trouble shifting from 1st to 3rd gear and acted like it was going to stall out and then die in the middle of the road while I was in the car with my 2 children. The dealership we took it to was not able to duplicate the limp mode, but has documented that they did witness hesitation and sluggishness while test driving it. I cannot validate that it was test driven cold immediately as requested as all their test drives were done without me. Due to the vehicle not accelerating as it should normally, I feel the vehicle is very unsafe and unreliable as well. I’m willing to provide more documentation, and our car is available for further inspection. I did request the help of a Hyundai customer relations case manager who stated Hyundai is aware of all of the drive-ability issues I have stated and he said they are hoping to provide another software update, but that time frame is unknown. Dealership mechanic stated the same thing and believes our issue is related to the 9C2 update. The manufacture has not inspected the vehicle, but we would absolutely love them to if they would. There have been no check engine lights come on before or after this update, only misfire codes came up after the update which dealership has those, and since the dealership was unable to witness it going into limp mode while driving it, they could not gain the much needed data that pinpoints the exact problem. We were advised to warm up car and rev up the RPM to above 2,000 before driving.

Filed Jul 8, 2026 · Engine, Fuel system · FL

After a recall repair (Campaign 9C2) was performed on my vehicle, it developed a hesitation and lack of acceleration issue that did not exist before the repair. The vehicle exhibits rough or delayed gear shifting, a noticeable lack of power/acceleration, and behavior that feels like the engine is not receiving adequate fuel. This occurs both during cold start and after the vehicle has been driven and is fully warm. I returned the vehicle to the dealership (Wallace Hyundai), where the service advisor personally test drove the car with me and confirmed he could feel the hesitation firsthand. Despite this, the dealership stated no issue was found and advised warming the car up for 1-3 minutes before driving as a workaround. I tested this exact recommendation, and the issue returned even after the vehicle was fully warmed and had already been driven. Hyundai Motor America's National Consumer Affairs department has stated this is "under review" but has also described the hesitation as "normal" cold-start behavior related to catalyst warm-up. This does not match what I am experiencing, since the issue also occurs when the vehicle is already warm, and their own dealership's advisor confirmed the problem exists. I have also noticed a decrease in fuel efficiency (MPG) since the software update associated with this recall. This issue directly affects the safe operation of the vehicle — specifically the ability to accelerate reliably, including in situations like merging onto highways or pulling into traffic, where a lack of power could result in a collision. I do not consider the vehicle safe to drive in its current condition.

Filed Jun 22, 2026 · SC

What component or system failed or malfunctioned, and is it available for inspection upon request? Multiple systems have failed sequentially — engine (replaced at ~84,000 miles), catalytic converter (replaced post engine replacement), and transmission (currently stalling, pending replacement authorization from Hyundai Corporate). The vehicle is available for inspection upon request. How was your safety or the safety of others put at risk? The vehicle stalls during the first few miles of every drive before stabilizing. This creates an immediate risk of accident on public roads, particularly at intersections, highway on-ramps, and in traffic. Despite this known safety hazard, the dealership returned the vehicle to me unrepaired on June 22, 2026, and deemed it safe to drive. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. Fort Mill Hyundai (805 Gold Hill Road, Fort Mill, SC 29708) has confirmed they can physically feel the stalling issue but stated they do not have sufficient data to submit to Hyundai Corporate for transmission replacement authorization. An independent mechanic also previously confirmed the engine issue that the dealership initially dismissed. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Yes. Fort Mill Hyundai, an authorized Hyundai dealership, has inspected the vehicle multiple times over several years. The dealership is actively coordinating with Hyundai Motor America Corporate regarding the transmission replacement. Invoice reference: [XXX], dated June 22, 2026. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? Yes. Check engine and brake warning lights first appeared at approximately 64,000 miles. These lights recurred repeatedly every ~1,000 miles despite multiple dealership visits. Subsequent symptoms included engine hesitation and loss of power, fol INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INF

Filed Jun 11, 2026 · Engine, Transmission · FL

Following the completion of an official emissions recall software upgrade at Fitzgerald Auto Mall Countryside, Clearwater Florida, my 2017 Hyundai Santa Fe Sport (52,000 miles) now suffers from a severe loss of motive power and erratic transmission shifting/jerking during cold starts throughout day. The vehicle continues to hesitate during cold starts, making it impossible to safely accelerate from a stop into incoming traffic. I returned to dealership on 5/29/26 to address continued driving issues. The servicing dealership states they don't have a software fix and offer no mechanical fix. The dealership states they received an internal memo from Hyundai Corporate which instructed the dealership to tell affected owners to idle the vehicle for 1-3 minutes before driving to allow system adjustments. Forcing a consumer to wait out a dangerous powertrain defect in a running vehicle to avoid a roadway acceleration/loss accident is an unacceptable safety hazard. The manufacturers recall update has actively compromised the safe operation and motive control of this vehicle.

Filed May 6, 2026 · Engine · FL

Immediately following the implementation of Service Campaign 9C2 and TSB 25-01-087H - ECU Update for THETA II Emissions Logic Improvement, the vehicle exhibits poor drivability (staggering/missing/hesitation) until the engine warms up. This is most noticeable just prior to the shift from first to second gear.