2021 Hyundai Santa Fe: adaptive cruise control problems

Filed Apr 9, 2026 · Engine · NY

My vehicle loses power on the highway intermittently. I had my car set on cruise control at 55 and with no other vehicle in front of me the speed decreased to 45. It frequently sputters going up hills. My car has had 4 oil leaks.

Filed Jan 18, 2023 · Transmission · 21,000 miles · TX

The contact owns a 2021 Hyundai Santa Fe. The contact stated while driving 60 MPH with the Adaptive Cruise Control mode activated, the contact heard three beeping sounds, and the vehicle lost motive power. There was no warning light illuminated. The contact veered to the side of the road. The contact restarted the vehicle and continued driving. The contact stated that the vehicle made the beeping sound again while driving 50-55 MPH however, the vehicle had not lost motive power. The dealer was notified of the failure and informed the contact that the vehicle was safe to drive because there was no warning light illuminated. The contact continued driving. The contact stated that upon restarting the vehicle, the Powertrain Control Module (PCM) warning light was illuminated. The vehicle was towed to the dealer where the transmission was flushed; however, the failure reoccurred 2 weeks later while driving. The vehicle was taken back to the dealer where the transmission fluid was refilled; however, the failure persisted. The vehicle was taken back to the dealer where it was diagnosed that the transmission needed to be replaced. The vehicle was not repaired. The contact related the failure to the federal safety agency Campaign Number: 22V746000 (Power Train) for which the VIN was included. The manufacturer was not notified of the failure. The failure mileage was approximately 21,000.

Filed Sep 28, 2021 · Driver assistance · AZ

Smart Cruise Control relies on the inconsistent and consequently unreliable performance of the of the front-mounted radar. Otherwise-reasonable operation of the Cruise Control would abruptly terminate 1/3 to 1/2 of the intended use-time, illuminating the master warning light (the amber triangle with internal ‘!’) that was accompanied by either a ‘1’ or ‘2’ encircled by red and may or may not have included the Collision-Avoidance warning light. Subsequent examination of the rectangular shield in the center of the grill very rarely revealed more than 2 bug remnants. When the Smart Cruise Control was in operation it would abruptly apply the brakes when approaching or passing a truck in the lane to taffiche right. There appeared to be no similar conditions to the size or shape of the truck or trailer when these events would occur. None of these events applied to congested tr conditions, just otherwise open road. The ’21 Hyundai Santa Fe does not appear to accommodate any mechanism to revert to conventional cruise control, omitting the influence of the erratic front radar system. Trips to two dealerships have yielded no redress to this malfunction.

Filed Aug 20, 2021 · Acceleration, Driver assistance · WI

This vehicle is the first Santa Fe that only comes with adaptive cruise control and there is no way to disable it and set regular cruise control. Here are just a few examples of the safety risk. We were on State Highway 29 which is a rural 4 lane highway. There were 4 cars near us. Our cruise was set for 70mph. A vehicle came in front of us to pass which it did. There was no issue. However, our vehicle saw this as a threat and our vehicle slowed from 70mph to 50mph until the other vehicle was out of the set car length distance. Meanwhile the other cars around us had no indication or warning why we would have slowed down this much and we were nearly rear ended. There was screeching of tires and brakes suddenly applied by the other vehicles. All for nothing. I am on the highway with the cruise set at 75mph when again vehicles will come in front of me and my vehicle slows from 75 mph to 54mph, causing the surrounding vehicles to not know what is going on and I hope they are paying attention because there is nothing really going on other than normal driving. It is terrifying to have your vehicle control itself and you don’t know when it will start to accelerate again so for the most part, I am shutting the cruise control off and on constantly. At our most recent Hyundai service appointment for this problem, we were told by Hyundai Care Manager that this is exactly how it’s designed and there is no problem. And we’ve been told just simply don’t use the cruise control at all. That is not a solution. We feel like all these “safety” features are creating a sense of driver coma on our roads. Instead of the left lane being used for faster cars as a passing lane, the adaptive cruises are creating a chain of vehicles that are well under the speed limit

Filed Aug 4, 2021 · Driver assistance · NY

Unnecessary emergency brake activation has occured 3 times. Vehicle lease new 3/31/2021. 1. First incident late April, early May at approximately 1,000 miles. Cruise control was not on and car abruptly stopped when there were no other vehicles in front of mine. Traveling at about 35 miles a hour on local two lane road. (Activation setting on normal) 2. Brakes activated at highway speed of about 60 mph. Car was passing on right side. No threat in front of vehicle. Cruise control was off. (Activation setting on normal) 3. Was following well behind the car in front of me at approximately 30-35 mph. Other vehicle turned right into parking lot and was completely off the road when brake warning appeared on dash. (Activation setting on "late" warning) We are concerned we will be unnecessarily rear ended and causing a multi car accident. Vehicle was in for service 8/2-8/3/2021. Dealer did all they could including 62 mi test drive. Per Hyundai, no parts were replaced due to the inability to dupicate the problem.

Filed Jul 28, 2021 · VA

Engine shut off while driving 70mph in the middle of the mountains in PA during a road trip from VA to MI, 2 adults and one child. No Warning No Check Engine lights No alarms, just shut off. I tried to press the ignition start button but it would not function until the engine was in park, gave no warning or alarm when I pressed it, the engine start button wouldn't respond. At Shutoff, going ~70mph, I had: Zero acceleration Zero power No blinkers No Instrument Cluster (LED Cluster screen installed) The only way I could signal to merge onto the shoulder was to turn on the hazard lights and attempt to merge from the fast lane to the shoulder, completely crossing faster traffic with no blinkers to guide my merging and warn other drivers on the highway. Instrument cluster turned white as if it was being reset and music was still playing in the car Bluetooth connected to my phone. Conditions of the vehicle during shutoff: 1. Adaptive Cruise Control was on, set to 3 car lengths of distance. 2. Lane Keep Assist was on 3. Lane Departure Warning was on 4. Bluetooth was connected 5. Navigation was active and guiding Once I was able to merge to the shoulder, I shifted into park and sat there for about a minute while I tried to calm my family down from what had happened so unexpectedly. After a minute or so, I was able to start the vehicle back up and nervously proceeded back on the highway to continue on with the rest of the trip. I immediately contacted Hyundai when I returned to VA and explained the issue, they took the vehicle into the service department of the dealership that I purchased the vehicle from. Hyundai kept my vehicle for 2 days and drove it "120 miles" but were unable to recreate the problem. They stated that all the systems checked out and there was nothing more they could do. I have since created 2 cases with Hyundai Corporate office to rectify this issue to no avail. Without the issue being recreated, there is nothing they will do for my family.