2025 Hyundai Ioniq 5

While traveling at highway speeds, the vehicle suffered a catastrophic and sudden loss of motive power. This resulted in a dangerous situation with no immediate ability to maintain speed in traffic. The manufacturer (Hyundai) identified a failure in the Integrated Charging Control Unit (ICCU). Despite a formal 'Notice to Cure,' the manufacturer refused to replace the 12V battery which was stressed during the failure, potentially leading to a repeat high-speed power loss event. This is a known issue with the E-GMP platform (Ioniq 5) that poses a significant unreasonable risk to public safety.

The vehicle exhibited charging failures on multiple occasions over the course of several days after being connected to a Level 2 home charging unit overnight. On repeated mornings, the high-voltage battery was found to have not charged. The vehicle also exhibited intermittent slow charging behavior during this same period. Approximately six months prior to the charging failures, the 12-volt auxiliary battery was found to be completely discharged. During this same period, the vehicle was started on one occasion to find that every warning and alarm indicator on the dashboard had triggered simultaneously. The vehicle was completely inoperable at that time. After several minutes, all warning indicators cleared and normal operation resumed without any intervention. The vehicle was brought to an authorized Hyundai dealership on March 6, 2026, where the technician diagnosed the root cause as a failed Integrated Charging Control Unit (ICCU). The ICCU is responsible for managing both high-voltage battery charging and maintaining the 12-volt auxiliary battery; a failure of this component can result in loss of charging capability, auxiliary battery drain, and potentially a complete and sudden loss of vehicle operability. As of the date of this report, the vehicle is awaiting parts with an estimated repair time of approximately one week. The repair is expected to be covered under the manufacturer's warranty. This failure occurred with fewer than 10,000 miles on a 2025 model year vehicle. Based on publicly available owner reports and online forums, ICCU failures appear to be a recurring issue across multiple Hyundai IONIQ model variants.

While driving, car displayed a check electrical vehicle system warning light. The 12 volt battery completely died and could not maintain charge resulting in slower and then complete loss of propulsion. Towed to dealer and the following Monday determined it was an ICCU failure. Part is back ordered but verbally told on 2/24/2026 that part would be delivered in two weeks. We'll see!!! If this issue occurred while driving on an interstate at full speed with traffic it seems this might result in an accident since the max speed dropped to 25 MPH and then 12MPH after warning before being able to safely pull over.

On [XXX] while driving the car on a city street in Northhampton, MA, I heard a loud "pop" and there were multiple warning lights, beeps and messages indicating there was a problem with the electrical system. The car slowed dramatically and I was unable to drive at a safe speed to keep up with traffic. The car slowly lost power and I was able to pull over to the side of the road. The temperature was 15 degrees F - very cold, no heat and I had to stay with the car in freezing cold temperatures to await transport via tow to the local dealer. The tow service required that someone be with the vehicle in order to receive a tow. The dealer diagnosed the car with a failed ICCU - a well-known, increasingly common issue with these cars - and said there were already 10 Ioniqs on the lot awaiting replacement ICCUs. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My Ioniq5 experienced a failure of the Integrated Charging Control Unit (ICCU) while driving. There was a loud "pop" noise from the back seat that occurred while driving, and afterwards the car experienced an unexpected braking/deceleration and was unable to maintain a speed over ~30MPH. After the "pop" noise -- a "Check electric vehicle system" alert appeared on the dash, and an alert that the car had entered a limited power state also appeared a few minutes later. My safety was put at risk due to the car unexpectedly decelerating and then losing the ability to maintain speed while driving on a busy highway. Other's safety was put at risk due to my limited ability to maintain speed and not impede traffic. There was no warning's prior to the sudden failure to indicate there was anything wrong with the vehicle. The car needed to be towed to the dealer due to the limited state the car was put in. It was confirmed at the dealership that the ICCU had failed and needed to be replaced. It was also confirmed at the dealership that the replacement part was the same as what had failed, which is concerning for mine and other safety that this is at risk of occurring again.

The 12V system battery failed to keep a charge and the vehicle slowly reduced maximum speed until it fully died causing the car to coast to a stop on a 55MPH highway. At 9,500 miles on the odometer the ICCU has failed. The part is on backorder and my car has been in the shop for three weeks with no estimated completion date. A LOT of IONIQ 5 owners are encountering the ICCU failure.