What 29 owners told NHTSA about the 2021 Hyundai Elantra Hybrid

The contact owns a 2021 Hyundai Elantra Hybrid. The contact stated that while driving 60 MPH during ice and snow, the engine revved, and there was an abnormal sound coming from the Hybrid battery. While turning, the contact stated that the vehicle had unintendedly accelerated. Additionally, the tire pressure warning light was illuminated. The contact believed that the failure was related to the Hybrid battery. The vehicle was driven to the residence, where it remained parked and was not driven since. The manufacturer was notified of the failure. The failure mileage was 44,900.

NHTSA ODI 11708400

The headlights and back lights turn off at random times when the headlights are on the automatic setting. This problem happens very frequently at night, putting my family at risk when the lights go off and cannot see what is ahead of us. In addition to a cop pulling me over for not having my lights on and he asked me if I was playing with the lights since they were going on and off and luckily the cop did not give me a ticket when I explained and he saw the problem (he advised me to get on this website and to make a report). I have reported this problem to the Hyundai dealership for the past 3 years and I don’t even think they take the time to investigate. The dealership just keeps telling me that with another update in the software is going to get fixed. But that is not the case. This is a very dangerous problem that is going to get someone killed. Need to be fixed

NHTSA ODI 11672296

Check Hybrid System alarmed in heavy traffic and derated my car and put me in a very dangerous situation.

NHTSA ODI 11671060

I am writing to report a serious and ongoing safety issue with my 2021 Hyundai Elantra Hybrid that remains unresolved despite multiple visits to Hyundai service centers and independent repair shops. I’ve also found numerous consumer discussions online describing nearly identical issues with the same model and newer Elantra Hybrid models, suggesting this may be part of a wider systemic defect. The core issue lies within the vehicle’s hybrid system. Shortly after a recent system/software update performed at a Hyundai dealership, a warning message began appearing at random intervals stating: “Check Hybrid System.” This typically first appears after extended driving — often around 3 hours — but once it occurs, the issue worsens if I continue to drive. Each time the warning appears, the vehicle suddenly and drastically decelerates without driver input, becoming dangerously slow and unresponsive, even while traveling at highway speeds. This creates an urgent safety risk, as I have had to maneuver off the road quickly to avoid collisions. After the initial warning, if I attempt to drive the vehicle again without sufficient downtime, the warning reappears much more frequently — sometimes within minutes. The only temporary relief is to stop using the vehicle and allow it to rest for at least six hours, after which the issue may temporarily subside. In every case, I must use the 12V battery reset button to restart the car, which I suspect may be clearing diagnostic codes before they can be properly recorded. Notably, the check engine light disappears after this reset, even if it was previously displayed. Given that the hybrid battery is located beneath the rear passenger seat, I am deeply concerned that if there is an underlying thermal or electrical issue, it could pose a serious or life-threatening risk to passengers. To date, no dealership or technician has been able to duplicate or permanently resolve the problem.

NHTSA ODI 11661670

I have a safety recall is with a Rear view camera that hasn’t had a solution.

NHTSA ODI 11632655

The Hybrid charging system fails once the vehicle is above 75 mph. After about an hour or two, the vehicle will die on the highway. This is a reoccurring issue putting our safety at risk. The dealership cannot find what the problem is. Online forums show similar issues with dealerships unable to solve the problem.

NHTSA ODI 11624498

At around 93k miles my HECU unit apparently malfunctioned at the same time as the left front tire speed indicator. All of my safety features ABS, adaptive cruise control, lane departure, lane keeping etc do not work because of this.

NHTSA ODI 11621727

The contact owns a 2021 Hyundai Elantra HEV. The contact stated while driving 65 MPH, the vehicle started to lose motive power with a battery warning light illuminated. The contact stated that on several occasions, the vehicle had to be turned off and restarted for the vehicle to recharge and restart. The vehicle was taken to the dealer, but the vehicle was not diagnosed or repaired. The contact informed the dealer that the failure was intermittent and within an hour the dealer stated had replicated the failure. The manufacturer was notified of the failure. The failure mileage was approximately 52,000.

NHTSA ODI 11592150

When gas is pressed (even to floor) in drive, vehicle stalls, does not accelerate. Then vehicle jerks into propulsion after revving. Other instances, at deceleration the car will jerk and shake to a stop. I have mentioned the problem at every scheduled maintenance

NHTSA ODI 11586175

I was driving on the Highway at the posted speed limit when the warning "Check Forward Safety System" came up and remained on my dashboard. The cruise control stopped working also. The light remained on even after stopping and starting the car and has remained on ever since. I have never been in an accident nor has my computer system reported any collision. My Hyundai Blue Link app gives me the following DTC: C162078. It started on [XXX]. My collision detection system does not appear to be working at all and my cruise control no longer works. I'm very concerned about it malfunctioning based on other entries on the nhtsa.gov website. I took the car to Hyundai Service Center and they are trying to convince me this is due to a collision and warranty will not be covering it. They tried to charge me for diagnostic even though I already had the error code on the Hyundai BlueLink App. They confirmed that my computer has zero reports of any collisions. The service tech said, and I'm quoting, "The system is very sensitive and a swift kick could cause it to malfunction." That sounds like a manufacturing defect to me. I have never been in an accident with this car, there is zero visible damage to the front bumper, and my computer has no report of an accident. The dealership urged me to contact insurance. My Major Insurance Company told me this was absurd, would never be approved, and is clearly mechanical. They also mentioned anecdotally that this problem has been coming up a lot for them with modern Hyundai models. Then I called Hyundai Corporate and they have escalated the issue, agree it sounds mechanical, and will be contacting me in 3-5 business days. They apologized profusely so I am still holding out hope for warranty coverage. I believe the dealership is trying to blame me for this mechanical failure to avoid expense on their end. I have had many software-related issues with this car. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11572957

I keep getting intermittent HEV warnings and 12-volt light. The engine then shuts down and I have no power. This has occurred several times while on the highway and this creates a safety hazard. I have been fortunate enough that this happened while I was close to the shoulder, otherwise, it could have been critical. - The failed component(s) are the 12 volt battery and engine shutdown - With the vehicle being without power while on the highway puts other drivers and myself at risk of an accident - I have taken the vehicle to two different Hyundai dealers and they have not resolved the problem - The issue was escalated to the manufacturer Hyundai Motors and they have not resolved this issue. - The 12v battery light and an HEV warning light comes on and then the engine shuts off - This issue has been happening intermittently for the past year and I first notice it on October of 2022

NHTSA ODI 11554043

This is my second time contact and reporting this issue about the vehicle surging unexpectedly and you cannot get it to slow down except by keeping your foot on the brake and pulling off the road. This has happened multiple times since I have had this vehicle. Recently, I had the car in for service and they said they did a recall for the software to stop this condition from happening again. However, 1 month later, it happened and this time it was the worst I have ever experienced as I kept my foot off the accelerator - it surged over 15mph from the speed I was originally at with me doing nothing and it was still gaining. My car was trying to accelerate with my foot on the brake and I had to cross lanes of traffic to get to the side of the road to restart the vehicle. The reason that it was the worst, is that I literally could not begin to control this vehicle. Other times it has happened and I could at least go for a little bit as long as I kept my distance from other cars but this acceleration was beyond out of control. I could have caused an accident or hit somebody. No warnings appeared, no messages or lights.

NHTSA ODI 11551172

My 2021 Hyunadai Elantra HEV Blue 12v battery light comes on and I lose power to the engine and all internal electrical components. It has happened while driving on the highway and it is a safety concern. I have addressed it with the dealership and they stated there were no codes and they canot replicate.

NHTSA ODI 11541657

the h e v warning light comes on when driving. the hybrid battery disconnects from the engine and the car is undriveable. have to pull over, stop the car, turn off the car and then reset the hybrid battery. this has happened twice in last week. thank fully i was able to pull over safely, but this a dangerous situation for me and other cars around me. the car had been taken to the dealership just two weeks ago and they were unable to diagnose the issue

NHTSA ODI 11528504

I was driving on a 40mph speed road at 45 mph and the car stopped accelerating abruptly and remained stuck at 20 mph even thou my foot was on the gas pedal. I had to put the caution lights on and get to the side of the road. I had every car behind me honk and yell when passing by. This could have been a big crash. I have the video of this when I was driving. This happened various times, in December, Feb and last week.

NHTSA ODI 11525448

So the car will come to a dead stop. Then when I give gas, it will not go for 1-2 sec, then all of a sudden it go at high speed by itself. Even when I brake, it will feel like as if I have stepped onto gas. Very dangerous

NHTSA ODI 11521781

On a few occasions (3?) the cars’ automatic emergency braking feature activated while driving at both highway and normal speeds. On none of the occasions was there inclement weather or a “slick” condition on the road. The feature would activate, give a visual and audible warning, and then de-activate within a few seconds. When the feature activated, I felt the car jerk a bit to slow down, and sort of swerve in one direction before righting itself. There is a possibility that the feature activated because I had manually enabled the Auto Hold feature as well which I usually do.

NHTSA ODI 11521478

Car will accelerate when pressing on brakes. Once car is able to turn off, the problem does not repeat. This has occurred at least 3 times with the same car and random times while on the road. Dealership is unable to replicate the brake issue every time the car is brought in.

NHTSA ODI 11516987

Sometimes upon depressing the accelerator the engine does not respond. The car does not move in a traffic situation. Putting the car in park, shutting it down and restarting makes it go away for a while. Getting on and off the highway is especially dangerous. This has happened intermittently for the past 1-1/2 years. The dealer says that they cannot reproduce the problem. So, they cannot repair it.

NHTSA ODI 11512047

While driving in stop and go traffic this morning (02/06/2023), at approximately 8:45 am, my Hyundai Elantra began accelerating on it's own. I applied the brakes and the car behaved as though I slammed on the brakes. The acceleration and braking issues happened multiple times during this drive. After the first incident, I shifted the car into neutral, (when it happened subsequently) until it quit accelerating, which was a couple of seconds. I have scheduled service at the Hyundai dealer for tomorrow morning (02/27/2023)

NHTSA ODI 11505880

The contact owns a 2021 Hyundai Elantra Hybrid. The contact stated that on multiple occasions while the vehicle was idling, right before releasing the brake pedal, the vehicle did not immediately accelerate forward while depressing the accelerator pedal. Additionally, while driving at various speeds, the vehicle experienced unintended acceleration. After stopping and turning off and restarting the vehicle the failure was self-corrected. The vehicle was taken to the local dealer who was unable to duplicate the failure or detect the cause of the failure. The manufacturer was also notified of the failure, but no assistance was offered. The failure mileage was 2,000.

NHTSA ODI 11503853

Our problem started a few months ago. At first, we thought it was just a fluke, but this issue has happened too many times to be so. The issues are, the car does not accelerate when we depress the accelerator, we see the tachometer move, but the engine is not actually accelerating. Then at times it will accelerate on it's own, while sitting at a red light, the car tries to move forward despite having our foot on the brake, it acts like we are trying to push the accelerator and the brake at the same time. Even worse, while driving, the car will go into accident-avoidance mode, even though there is nothing in front of us. There are no errors or codes populating on the dash.

NHTSA ODI 11499829

I had reported that the horn wouldn't work..especially in cold weather last winter. The horn would work by the time I arrived at dealer. Told nothing they could do as it was working. It has happened 3 times in the last 2 months, finally totally nonfunctional the past 3 days. I called, stopped at dealer to have it checked. The car was returned to me with service person telling me that the horns diaphragm is stuck. When asked if working , he said for "right now." He told me a new horn(s) were ordered. I asked him what he did: he replied, I hit the horn with a rubber hammer until it worked! Well, one mile or so down the road, it didn't work. I checked the internet and there are MULTIPLE instances listed of ongoing issues with the horns on Hyundai vehicles. In the end, I am driving with some hesitance as the horn isn't working. THIS IS NOT ACCEPTABLE IN A CAR 1.5 years in my opinion. Again, after checking on the NHSSA website, NO RECALLS or MENTION of this safety issue! Please escalate this to TOP PRIORITY! If not, anyone's injury or death is worth the wait!

NHTSA ODI 11497846

The contact owns a 2021 Hyundai Elantra. The contact stated that while slowing down and making a left or right turn, the vehicle independently accelerated. The contact also stated that while at a stop, he depressed the accelerator pedal and the vehicle accelerated at an abnormal speed. The contact stated that he applied extra pressure to the brake pedal to stop the vehicle. No warning light was illuminated. The vehicle was not diagnosed or repaired. The dealer was not notified of the failure. The manufacturer was notified of the failure, but the contact had not yet received a response. The failure mileage was approximately 15,000.

NHTSA ODI 11494714

The contact owns a 2021 Hyundai Elantra. The contact stated that on several occasions while decelerating, the vehicle would lunge forward and the engine would rev. The contact stated that the vehicle would shut off while stopped. No warning lights were illuminated. The vehicle was taken to the dealer where the failure was not determined. The contact stated that the vehicle was taken to the dealer three times where the failure was not determined. The failure recurred for the fourth time. The contact was awaiting a tow to the dealer Fitzgerald Countryside Hyundai. The manufacturer was notified of the failure and a case was opened. The failure mileage was 19,651.

NHTSA ODI 11477182