2023 Hyundai Ioniq 5

We are reporting a suspected thermal runaway incident involving our recently purchased used 2023 Hyundai Ioniq 5 and have significant concerns regarding the vehicle's safety. **Vehicle Information** * Purchased XXX, 36,662 miles * Clean inspection and no accidents per Carfax **Incident Timeline – XXX** Between 6:00 and 6:30 PM, while traveling northbound on [XXX] just past the [XXX] exit in [XXX], the vehicle struck a white piece of road debris that appeared flat, similar to Styrofoam (video available). There was no immediate loss of vehicle function. [XXX] The vehicle was then moved to the driveway for inspection after a low coolant warning appeared. Damage to the underside near the driver's side and observed blue coolant leaking from the area. The coolant reservoir under the hood was empty. Based on online guidance advising against driving a vehicle with a coolant leak, we decided to leave the vehicle parked in our garage overnight and arrange a flatbed tow to a Hyundai dealership the following day. The garage door was closed, and the vehicle was **not charging**. At approximately 8:10 PM, a burning smell was detected inside the home. Upon opening the door between the house and garage, smoke was observed. The family immediately evacuated, and XXX was called at 8:12 PM. The fire department arrived at approximately 8:18 PM and found the garage filled with smoke. At 8:30 PM, firefighters removed the vehicle from the garage. At 8:35 PM, flames were observed beneath the vehicle. Firefighters applied water directly to the fire until 11:00 PM, after which the vehicle was removed. [XXX] [XXX] [XXX] Manufacturer was contacted; denies any liability due to debris. However, we believe inadequate safety design contributed, including soft protection shield and poor location of coolant. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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.

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 AC

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.

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.

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.

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

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)

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.