Hyundai Santa Fe Sport hesitation problems

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 15, 2026 · Engine · NE

My 2018 Hyundai Santa Fe Sport (2.4L Theta II GDI, VIN [XXX], approx. 110,000 miles) has suffered a chain of engine and emissions-system failures that create a loss-of-power safety hazard. At about 80,000 miles, Hyundai replaced the original engine under warranty for excessive oil consumption, a defect Hyundai has acknowledged across the Theta II engine family. After only about 20,000 miles on that replacement engine, the catalytic converter failed and set a P0420 code. The vehicle now bogs down, hesitates, and loses power under acceleration. This is dangerous when merging or accelerating into traffic, where a sudden loss of power raises the risk of a collision. A restricted or failing catalytic converter causes exhaust backpressure and abrupt power loss, and the underlying oil consumption also risks low-oil engine damage and stalling. A catalytic converter should last far longer. This premature failure is consistent with the well-documented Theta II pattern in which engine oil consumption contaminates and destroys the converter substrate. It indicates the replacement engine Hyundai installed is itself consuming oil and damaging downstream exhaust and emissions components. I reported this to the dealer and to Hyundai. Hyundai declined to cover the catalytic converter, treating it as unrelated, even though its own warranty engine replacement is the direct cause. I am filing so this safety-related failure is documented. No crash, fire, or injury has occurred. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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 26, 2026 · Engine, Fuel system · NJ

Bought this as a used vehicle with around 77k miles. The SUV was running fine for a little while until I drove onto the highway. It eventually began to bog down and there was hesitation and jumping instead of acceleration. This continued my entire trip home with the check engine light on. The car was only driven for about 300-400 miles in the time I had it. When I brought it to have an oil change, they found metal shavings in the oil. From what I’ve been reading, this has been a common problem for this vehicle. It has been sitting in a Hyundai service center for at least a month now with no real responses from Hyundai themselves. They told me they would not fix the problem due to lack of maintenance from prior owners and that they were marking my title (doesn’t make sense since I bought this with a clean title). According to what Hyundai told me, this issue was brought up by a previous owner in January 2026 with no repairs. How can you change the status of my title while refusing to repair a problem caused by a manufacturers defect?

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.