2017 Hyundai Santa Fe: jerking or lurching

Filed Sep 27, 2026 · Engine, Transmission · MD

Immediately following the mandatory Hyundai Servie Campaign Update 9C2-ECU THETA 11my vehicle began exhibiting severe hesitation, very rough idling, jerking at slow speeds and when gear changes, difficulty going up inclines and almost feel at times as though it is about to lose power which poses life threatening situations especially when turning into traffic. I have reported it to the dealers who never once test drove the vehicle but said to me that they did and could find no problem, however they did make me pay for repairs which never fixed the problem. I returned three times with the same issue. They recommended a Fuel Induction Service and a Auto Trans Service. Spark plug change. Igniton coils change. Nothing worked!

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 31, 2026 · Electrical, Engine · NC

Cold-Start Hesitation & Rough Shifting: Following the 9C2 ECU update, my vehicle is experiencing a brief period of throttle hesitation, rough shifting, or jerky transmission behavior specifically during cold-start operations.

Filed Aug 24, 2026 · Electrical, Engine · NJ

My 2017 Hyundai Santa Fe, purchased new from Lynnes Hyundai in February 2017, has approximately 93,000 miles. The vehicle previously developed a significant oil-consumption/engine problem that was diagnosed by Hyundai, and Hyundai replaced the engine with a remanufactured engine. Approximately two weeks after the engine replacement, the check-engine light illuminated and DTC P1326 was identified. The dealership replaced the knock sensor. Approximately two weeks later, the check-engine light illuminated again with a recurring P1326 condition. The vehicle is currently at Lynnes Hyundai and has been there approximately three weeks while they attempt to determine the cause. Hyundai Techline is involved. Prior to the current repair visit, while traveling approximately 60 mph, the vehicle experienced a very forceful hesitation that jerked the vehicle. I immediately slowed down and pulled onto the shoulder. The vehicle continued to hesitate intermittently while I drove slowly to safety. I was concerned that the vehicle could lose power or shut down while I was driving at highway speed, creating a risk of a crash. The recurring P1326 condition has been confirmed by the Hyundai dealership. The vehicle and engine have been inspected by Hyundai/Lynnes Hyundai multiple times, including after the engine replacement. The current recurring condition has not been resolved. The check-engine light is the warning lamp associated with the current condition. I do not know the underlying cause of the recurring P1326 condition; Hyundai is currently attempting to diagnose it. The vehicle is currently available for inspection at Lynnes Hyundai.

Filed Aug 10, 2026 · Transmission · 63,036 miles · FL

The contact owns a 2017 Hyundai Santa Fe. The contact stated that while reversing, the vehicle jerked and shuddered abnormally. Additionally, the transmission hesitated, and the vehicle almost stalled. No warning lights were illuminated. The vehicle was taken back to the dealer where the contact was informed that the Service Campaign Number: 9C2 was completed. The contact was informed that the updated software was confusing the transmission and had caused the failure. The contact was informed that the remedy was not yet determined. In addition, the contact was informed that the dealer was waiting on instructions from the manufacturer. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 63,036.

Filed Jul 21, 2026 · Engine, Fuel system · VA

I own a 2017 Hyundai Santa Fe Sport 2.4L (VIN: [XXX]). On XXX, my vehicle received Campaign 9C2 (ECU software update for Theta II emissions improvement). Shortly after this update, I began experiencing a drivability issue that did not exist beforehand. Description of the issue: The problem occurs only after the vehicle has been sitting long enough for the engine to become completely cold, typically overnight. During approximately the first 1/4 mile of driving, the vehicle intermittently jumps, surges, or lurches while accelerating normally. Once the engine warms up, the symptom completely disappears and the vehicle drives normally for the remainder of the trip. There are no warning lights, no check engine light, and no diagnostic messages. The Hyundai dealer has had the vehicle for nearly a week but has been unable to reproduce the concern. Because the issue only occurs during the initial cold start and first portion of the drive, I am concerned that it may not have been tested under the same conditions in which I consistently experience the problem. I am not claiming that Campaign 9C2 caused the issue, but the timing is notable because the symptom began only after the ECU update was performed. I am requesting Hyundai's assistance in determining whether: - the ECU update was installed correctly, - any required adaptation or relearn procedure is incomplete, - there are any related Technical Service Bulletins or software updates, or - additional diagnostics should be performed during a true cold-start drive with live data recording. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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 Jun 26, 2026 · WV

Hi, I have a 2017 Hyundai Santa Fe sport and I recently went to the dealership to get my brakes done and that day they did the recall 9C2 which is a software update on the engine/transmission and the next morning when I drove my car the rpm’s were going up and my mph wouldn’t go past 15 mph for about a block down the road and the car jerked two times and then drove like normal. I call the dealership let them know about the issue and it’s never been an issue in the past and they set up a appointment I come in and they tell me if it’s not related to the brakes then I’ll have to pay $250.00 for a diagnosis test. Unbelievable I don’t believe this is a coincidence I have taken well care of my car and the past owner as well and the car doesn’t even have 100k miles. I have researched other people in the same situation as me and even read that Hyundai is recommended us to warm up our cars before driving now. It is so frustrating my car was perfectly fine until that recall and they won’t do anything about it.

Filed May 1, 2026 · Engine · CO

On 4/17/26 McDonalds Hyundai of [XXX] , dealership performed an ECU update for THETA II Emissions logic improvement (Hyundai campaign number 9C2). Ever since that time the vehicle has been lurching during acceleration. This happens particularly when the vehicle has been sitting for several hours. I reported this to the dealership on 4/28/26 (Scott, service manager) and to Hyundai on 4/29/26 (Hyundai Case Management #: 42610495). I noted to Hyundai that this same/similar problem has been reported by other owners ( see [XXX] ) INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 9, 2025 · Engine · AZ

My vehicle we bought from carvana has been jerking/misfiring and now with no warning on freeway it wouldn't give power stalling. There was no warning nothing no lights came up. I drive my kids in this vehicle I've taken it to multiple mechanics they say they couldn't find why it's jerking and it must be a manufacturer issue. I looked online and yes lots of issues with the make and model recall about the crankshaft sensor cause these issues!!!

Filed Jun 17, 2025 · Engine, Fuel system · VA

The car started jerking and the check engine light came on. I had to have it towed to my house. We can't get the car to do anything now. We get it started for 5 seconds, the engine completely dies

Filed Mar 13, 2025 · Engine · SC

I have only had my car 7 years and it is at 151,000 miles. I purchased it brand new in 2018. At about 15,000 miles I reported a burning smell under the hood and took kt in. The service department stated they did not smell anything. I continued to keep up with the service and had some issues with oil consumption. Hyundai did the test, but came back and advised it was okay and Hyundai's do this and it is okay. I later had an issue where it began jerking as if it were about to cut off after coming back from Virginia. I had it towed in and they advised it was nothing. Maybe bad gas. I was also told to just always check my car to put oil in it. I felt like this was crazy to have to carry around oil to put in my car within the same month of having an oil change or anytime. I have taken this vehicle in for this reason before I reached 150,000 miles and they would not give me an engine starting it necer had a recall. I explained that it has had issues where it stalled pulling out to get in traffic and I almost had an accident and it has had issues with the engine where it would jerk and hesitate. At this time, I recently went to Simpsonville for a funeral and it began the jerking and hesitation when we got into Fountain Inn. It was a lot and I was told by a mechanic that I needed a new engine. Hyundai would not help me. I called consumer affairs, I guesd with Hyundai and they took over 2 weeks and said there were no recalls and they couldn't do anything. I bought this car brand new, made sure I took care of it and this was what I got. Hyundai is a rip off and they do not guarantee anything. I will never buy from them again. Now I have been without a vehicle for over a month and not even anyone trying to get me a loaner, help with giving me a discount to purchase another vehicle or anything. I should have not had any issues with this car. I was having the exact issues of the recall vehicles but they state there were no recalls on it. Something needs to be done.