2025 Hyundai Ioniq 5

The Integrating Charging Control Unit (ICCU) failed while attempting to accelerate onto an Interstate Highway. The car then went into 'Limp' mode which only allowed a sped of 20 mph. Luckily I was able to get to the next exit without getting hit by car already on the highway going ~60-70 mph. The car showed both a 'battery warning' and a 'car over heating' symbol (the car has no engine, so assume it was the battery that over heated). The ICCU was recalled by Hyundai in the 2022-2024 Ioniq5 models, but was not recalled in the 2025 model (which I own). My suggestion is that the 2025 Hyundai Ioniq5 should be added to the the same recall as the 2022-2024 models since it is exhibiting the same problem.

1 Vehicle fails to start x 6 , dealer unable to fix, falsely identified 2 documented DTCs P31C507 specifically indicates a "possible condition with your Vehicle Control Unit (VCU) / Low DC-DC Converter (LDC)" dealer stated as charger problem when this is often associated with thousands of ICCU problems in this vehicle 2 many ADAS cruise control faults. A vehicle slows and, once stopped, at freeway speed on corners or when a large vehicle is in a nearby, separate lane. Fails to detect the vehicle in the next lane when activating lane change. 3. Keys and door locks fail electronic unlock and falsely lock the vehicle on approach. 4 decreased charging speed associated with a known prevalent main battery failure, and occasional main battery cell differential. 5 voice commands fail in the native and CarPlay app 6. Dealers unable to fix, give a delayed 2-week appointment and state that the car is out of service for a week or more with a loaner vehicle.

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.

I was on the highway going at approximately 60mph when the car without any warning reduced speed to first around 40mph and then to 20mph all within a matter of a few minutes, causing me to pull over to the side of the highway. Luckily, I wasn't injured. I exited the highway, called my insurance company Geico and had the vehicle towed to the dealership where I leased this brand new vehicle from just about 7 months ago on a 2year lease. The dealer was kind enough to provide a smaller loaner vehicle but had no idea when my car would be returned, as there were others with similar failures ahead of me that were waiting for the part to arrive. Apparently, this is a known failure issue of the ICCU that Hyundai has done a poor job of addressing. I continue to make my lease payments while waiting for the part to arrive. In the meantime, I wanted to let the government know of my experience and how this could have had a disastrous effect on my family and other families with a similar build.