What 381 owners told NHTSA about the 2023 Hyundai Ioniq 5 N

The vehicle repeatedly displays a "Stop Vehicle and Check Brake System" warning together with an ABS warning, accompanied by a loss of normal braking response. On XXX, while driving at approximately 60 mph on I-85 northbound near Exit XXX in [XXX], the warnings appeared and the brakes did not respond normally. I was maintaining a substantial following distance, and the braking system restored itself before I reached the point of needing to brake hard, so no crash or injury occurred. Had hard braking been required in that window, I do not believe the vehicle would have stopped as commanded. This is a recurring fault. The vehicle, purchased certified pre-owned and still under the Hyundai factory warranty, has been taken to the dealer (Ed Voyles Hyundai, [XXX]) three times for the same condition. On the first visit the Integrated Electronic Brake (IEB) unit was replaced; on the second, the Smart Junction Box was replaced; on the third, the dealer removed an aftermarket tracking device wired to the data link connector and referenced Hyundai TSB 24-GI-011H, representing the problem as corrected. The braking-loss event on XXX occurred after that repair. The vehicle has been out of service approximately 30 days total. Because the failure is an intermittent loss of braking response at highway speed, I consider it a serious safety hazard and no longer drive the vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11750932

The contact owns a 2023 Hyundai Ioniq 5. The contact stated that while driving at higher speeds occasionally, the vehicle suddenly lost motive power. The "Smart Smooth Cruise Control Conditions Not Met" warning message was displayed on the instrument panel. The contact restarted the vehicle as a temporary fix; however, the failure recurred. The vehicle was taken to a local dealer where it was diagnosed with an unknown electrical failure. The vehicle was repaired; however, the failure recurred. The vehicle was taken back to the same local dealer; however, the cause of the failure could not be determined. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 47,000.

NHTSA ODI 11749330

The ioniq 5 highway driving assist, which steers the car and keeps it centered in the lane, will disengage without clear warning - the small green steering wheel icon (which is at the top of the dash cluster) simply becomes grey and blinks, but there's no audible chime to indicate that the car has disengaged the steering assist. I have had multiple times on the highway where it disengaged and I don't notice (because I am looking at the road, not the dash) and one time on the highway it disengaged during a turn and hit the rumble strip, causing me to swerve back onto the road. My hands were on the steering wheel and I was paying full attention, but I was expecting the car to handle the turn, and it just disengaged without me noticing. Had there been another car in the middle lane or I reacted slower, it's likely a crash would have occurred. This has been documented as well on Reddit and confirmed by multiple owners, who have mentioned they have disclosed to the manufacturer: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11748381

Rear hatch window spontaneously shattered for no apparent reason. Car was parked in a Florida parking lot, no use of rear hatch and no use of rear defroster. I understand there is a potential class action lawsuit for the Ioniq 5 model years 2022-2025 for this problem.

NHTSA ODI 11748404

I have a 2023 Hyundai Ioniq 5 Limited and had the ICCU "popped" (failed) which took about two weeks to replace. This time we were lucky that in happened at our home but had we been driving the car would it would have completed died. We regularly drive from from [XXX] to [XXX] were there are large section of [XXX] with no cell service. Meaning potentially walking for miles in extreme heat or cold. Hyundai right now seems only interested in continuously replacing the part rather than actually fixing the route cause, making it so the car is not trustworthy or safe to drive long distances. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11747025

1. What component failed, and is it available for inspection? The Integrated Charging Control Unit (ICCU) failed. The vehicle is currently at the dealer's service center, so the failed component is available for inspection upon request. 2. How was your safety or others' safety put at risk? After parking and re-entering the vehicle following a grocery stop, the vehicle displayed "Check Vehicle Electrical System" followed by "Check Vehicle Power Supply" warnings. This occurred without warning while the vehicle was in normal use, and the vehicle had to be towed since it was no longer driveable. The sudden, unannounced failure of the electrical/power system created a risk of being stranded in traffic or in an unsafe location had the failure occurred while driving rather than while parked. 3. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The vehicle was towed to the dealer's service center, where the Hyundai-certified service technician confirmed the ICCU failed and informed us it needs replacement. 4. Has the vehicle been inspected by the manufacturer, police, insurance representatives, or others? The vehicle has been inspected by the dealer's Hyundai-certified service technician, who confirmed the ICCU failure. No additional inspection by Hyundai corporate, police, or insurance representatives has occurred at this time. 5. Were there any warning lamps, messages, or other symptoms prior to the failure, and when did they first appear? No warning lamps or messages appeared prior to the incident. The first symptoms were the "Check Vehicle Electrical System" and "Check Vehicle Power Supply" messages, which appeared suddenly upon re-entering the vehicle after a grocery stop, approximately one week after purchase (used) at roughly 8,000 miles.

NHTSA ODI 11745637

OnXXX, as we approached what I call the 6 o’clock position of a round-about in [XXX], we had braked almost to a full stop (0-5 mph) to wait on the car ahead of us to enter the round-about when we felt increasing movement. Despite braking, to wait on that car, our car with increasing speed started shoving that car into the circle. Fortunately, he was able to drive away from us, but that car had been damaged on the back and right side. With that obstacle out of the way, our car rapidly and exponentially increased speed - all while we were fully braking. Two witnesses said they saw our brake lights as we sped along. We hit the curb as we approached the 12 o’clock exit, and that turned us so that we crossed both lanes of the road and headed towards the far sidewalk and storefronts. When we hit that curb it pushed us diagonally to face the street again. Hard to estimate but we must have been doing 50 mph when we hit a very large brick planter and we finally were wedged to a stop when we slammed in between two vehicles parked parallel to the sidewalk. The motor ran for a few seconds after we stopped, and finally quit on its own. We KNOW the brake was applied the whole time; there were no visual or audible alarms from the car as we entered “UNINTENDED ACCELERATION”. Despite the incredibly strong impact (our car has been deemed totaled) the front air bags did not deploy. Only the driver’s side curtain deployed. The bumper of the parked transport van on our front left was damaged, and the small SUV on our front right was deemed totaled. No people were in those two parked cars; the first car was hit at the initial slower speed so those people were not injured. By some grace, no pedestrians were in our path or they would surely have been killed. The driver of our car (my husband) was miraculously not injured, but CT scans and x-rays showed I had several contusions and a fractured tibia that will require surgery due to brake, propulsion, no air bags. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11743216

All symptoms of a 2nd iccu failure. Pop noise heard. Warning lights came on 12v drained, vehicle towed to nearest dealer.

NHTSA ODI 11741290

Car indicated 12v battery was critically low and that I should stop safely. I was just starting it in a parking lot. This is a classic ICCU failure and the car is up to date on all recall updates. The car requires manual key unlocking for outside access at this point, and the rear hatch is only unlockable using the manual release mechanism which is recessed into the rear hatch and needs the key. The back two doors cannot be opened at all, from either direction and the handles don't work when the electrical system has failed and the child lock was engaged accidentally when it happened. This legitimately terrifies me for anyone traveling with back seat passengers who need quick exit. There isn't one.

NHTSA ODI 11739646

The Integrated Charging Control Unit (ICCU) failed on my 2023 Hyundai Ioniq 5. The vehicle stopped charging prematurely overnight via AC Level 2 charging and then refused to charge again at all. The ICCU is responsible for maintaining the 12V battery by topping it up during normal operation. No warning or check engine light came on, I was only made aware when I attempted L2 charging and the car would refuse to take the charge. I understand that with a failed ICCU, if I'm unaware of the failure (e.g., relies solely on DC fast charging which bypasses the ICCU), the 12V battery can deplete without warning while the vehicle is in motion, potentially causing sudden loss of vehicle systems including power steering, brakes, and other safety-critical electronics. The vehicle was parked at the time charging failure was discovered. No injuries occurred.

NHTSA ODI 11738922

The ICCU died a second time

NHTSA ODI 11738416

ICCU failed at 20,000 miles, 2 years after I first got the vehicle. Blue link showed the P1a9096 ICCU code failure. Car could not be driven for more than a few minutes then the message to stop safely came about and car would die. It took the dealer 2 months to replace the ICCU with the SAME defective part. It is only a matter of time before it fails again.

NHTSA ODI 11734215

My Hyundai IONIQ 5 has repeatedly lost 12V power and shut down. The vehicle had to be jumped by AAA multiple times. After being restarted, it died again, and after two days of use it was dead again. I am concerned this is related to the known ICCU / 12V battery charging issue affecting IONIQ 5 vehicles, which can cause loss of motive power or make the vehicle undrivable. The vehicle is currently at Hyundai Southern States in Raleigh, NC for diagnosis and repair.

NHTSA ODI 11733953

Iccu failure. Vehicle stops working completely

NHTSA ODI 11734182

See attached document for complaint.

NHTSA ODI 11733495

While charging my vehicle at home using a level 2 charger, the ICCU failed. When it failed, it caused a power surge and my level 2 charger “exploded.” It also caused the master breaker to trip, cutting the power off to my entire house. The vehicle no longer charges, will not drive over 25mph and has to be towed to a dealership for repair. Also, the level 2 charger is fried and no longer works.

NHTSA ODI 11730728

There was sudden power reduced and turn to the limp mode(Turtle symbol popped up). After pull over my vehicle to highway shoulder, the vehicle became total power loss. Unable to drive anywhere. It was a dangerous situation for my family. We waited tow car and took my vehicle to Hyundai dealership which located close to my house. They diagnosed my car and after a day. They told me it needs to be replaced a ICCU assembly and Fuse. There was no ETA for the parts. They provided me a loaner’s car. After about 15 days, they fixed and I was able to take my car.

NHTSA ODI 11730155

On XXXXX, while parked at a campsite approximately two hours from my home, the vehicle displayed an “electrical failure” warning on the dashboard. The vehicle had been parked for less than 20 minutes when this issue occurred. I contacted Hyundai customer support that same evening to report the problem (Case #XXXXXX). On April 4, 2026, the vehicle was towed via Hyundai roadside assistance to Winner Hyundai in Dover, Delaware, where Tracy is my current point of contact. This situation left my family of four, along with our belongings and pet, stranded without transportation. Despite significant effort, we were unable to secure a rental vehicle in the Dewey Beach area, even after contacting multiple rental agencies and the dealership directly. This was later resolved, and I am currently in a rental through Enterprise; however, the stress and uncertainty of potentially being stranded was significant and unacceptable. While at the dealership, my wife witnessed the tow operator unloading the vehicle without proper equipment to safely lower it. As a result, the vehicle’s hitch made forceful contact with the pavement and became lodged. Multiple dealership employees observed the incident. After considerable effort to free the vehicle, it was released abruptly and rolled into another vehicle on the lot, causing additional damage. An argument then occurred between the dealership owner and the tow operator, which my wife was forced to witness. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11730289

On 11/7/25 , we were driving my 2023 Hyundai Ioniq 5 to a friend's home in rural [XXX] , a trip of approximately 160 miles. At around 5:00 PM, we stopped about halfway to our destination to charge the battery. The car would not charge above 47%. While we continued to attempt to charge the battery, the console displayed a Check Electrical System Warning message, and we received the DTC P1AA700 via BlueLink. We were concerned about our safety on the drive up to the mountains. We were afraid the car would stop running on the highway and cause an accident. We were also concerned the car would die in a remote area and we would be stranded. However, the dealership was closed for the weekend. We drove carefully to our friend's home. I contacted Stevens Creek Hyundai on 11/10/25 and arranged to bring the car in on 11/11/25. It had 13,652 miles on it at that time. Eventually, the dealer confirmed the DTC P1AA700 and said they would need to order a new EGMP battery. The car was in the shop for 128 days, waiting for Hyundai to "build a battery" in [XXX] . Eventually, Stevens Creek Hyundai replaced the EV battery and I picked up the car. Given the delay in repairing my car and the growing evidence of Hyundai battery failures, we wanted to report this problem to the authorities. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11729574

7 incidents of electrical drive problem incidents 1-3car would not start despite full battery Incident 4 same thing and car went to dealer, they said know problem and they would fix it overnight by downloading new software and charge about 400 for new 12V battery Incident 5 While on freeway using cruise control card speed varied wildly I disabled cruise control and with manual throttle same problem Incident. 6 In middle of traffic car went blank no lights or anything. I tried to restart 3 times and nothing, so I sat back and was in process of calling for tow. I did nothing and car violently accelerated and turned into steel pole. Only injury I had was bump on head that went away. As soon as the ghost mode engaged I hit the brake which likely prevented more damage to me, but front end of car was damage Incident 7 While I was detained someone else drove car to dealer and driver reported felt like driving on ice with rapid direction and speed changes Currently at dealer where neither dealer or Hyundai will take of problem and I get run arround from Hyundai and dealer. Dealer claim the don’t know is the problem. Dealer has had car for approximately 65 days Bottom line, the car is totally unsafe to drive and very dangerous

NHTSA ODI 11729695

While driving the vehicle, the ICCU failed. The vehicle shut down in the middle of traffic without any warnings.

NHTSA ODI 11729262

On Mar 29th, I got a 12v battery low voltage warning sign at 4pm. Jumpstarted the car and drove back to the home. On Mar 30th, car would not start so I had it towed to Downey Hyundai by roadside assistance. On Mar 30th, 12:41pm dealer confirmed that the it will need an "ICCU" and have ordered the part, but there are no loaners and no ETA for the part at this time. Problem has been reproduced and confirmed by dealer. There were no other warning signs prior to the failure.

NHTSA ODI 11728697

I am writing to notify you of an Integrated Charging Control Unit (ICCU) failure on my 2023 Hyundai Ioniq 5, purchased in October of 2023. While driving home on March 4 2026, the dashboard displayed the warning "Check vehicle electrical system," and then a "pull over safely" warning. I had to leave the vehicle in a parking lot and walk home. It was towed to a dealer on March 5, 2026 to diagnose and repair the problem. The car has just under 17000 miles on it. I was told the dealer was swamped with Ioniqs with this problem and had no ETA for parts. Fortunately they will be able to repair our car next week. Hyundai claims the replacement part has been redesigned to address the problem. Interestingly, I'm reading that Hyundai has issued a recall for some vehicles of this make and model year for this very serious issue; mind bogglingly we received no such notice.

NHTSA ODI 11728740

Failure of Integrated Charge Control Unit (ICCU). Vehicle stopped charging 12V service battery from main high voltage battery. Displayed "Check Electric Vehicle System" followed by "Stop vehicle and check power supply". Vehicle to operate normally though Cruise Control stopped working. Continued to drive the few miles to our home. Once home checked service battery with battery monitor. Showed 12.1V and did not show battery being charged with vehicle ON (Ready) or OFF. Had vehicle towed to Hyundai service facility where the ICCU failure was confirmed.

NHTSA ODI 11728787

My vehicle lost power as I was driving after warnings from the electrical system. The vehicle was towed to a Hyundai dealership where it was diagnosed with ICCU failure. The ICCU system was replaced by dealer.

NHTSA ODI 11727468