2025 Hyundai Ioniq 5 Transmission Problems

Owner reports

Selected complaints filed with NHTSA by 2025 Hyundai Ioniq 5 owners, lightly cleaned up (personal details are redacted by NHTSA).

The ICCU (Integrated Charge Control Unit) failed. Fortunately I was in a parking lot at the time, as the vehicle limited its top speed to around 25 mph. Had the failure occurred on a highway it could have caused a collision. While this is a 2025 model year Ioniq 5, the ICCU hardware (part 36400-1XAA0) remains unchanged across all Hyundai/Kia/Gensis vehicles sharing the eGMP platform. NHTSA previously issued recall 24V-868 intended to address such ICCU failures. While the modified software is included from the factory in the 2025 model year Ioniq 5, it appears that the 24V-868 recall is not a complete fix. Indeed, ICCU failure continues to be one of the most commonly reported owner issues, both for vehicles which have already had the "fix" from recall 24V-868 and for newer vehicles outside of the recall's scope. …

On the afternoon of Saturday, December 12th 2025 I was preparing my car for a trip an hour north and back to drop my daughter off with her grandmother. I was charging my car with my Level 2 charger and preheating my car. Upon leaving for the trip, within a half mile I heard a loud popping sound coming from the rear of the vehicle and immediately had a warning on the vehicle stating "Stop Vehicle and Check Power Supply". The vehicle soon started to lose drive power, and I had to perform a U-turn and then parked at the nearby Quaill Volunteer Fire Department to perform a basic safety check. Knowing that I probably had the Hyundai Ioniq 5 ICCU issue, I knew that my car would soon have no power so I waited for an opportune time to leave the fire station to coast back to my house. After arriving home, I contacted Hyundai Roadside Assistance and my car was soon towed away. …

On [redacted] my there was a loud pop from the rear of the vehicle and electric vehicle warnings popped up on my dash. I turned around at the light, and as I drove I could tell that the vehicle was slowly losing power. Speed was limited to 30mph. Barely made it back home before the warnings on the dash told me to immediately stop driving. Vehicle was towed to the dealership, and they informed me on January 8, 2026 that the ICCU had went out and blown a fuse, so they needed to replace both. The car is unable to be driven until this is replaced. The current odometer reading is 3,390 miles. I called yesterday, January 21st and was informed that Hyundai has the ICCU on backorder and it will be at least two weeks before they can update me again. I've reached out to Hyundai Motor America National Consumer Affairs. …

Diagnosis: ICCU and fuse failure. Situation: 1/17/26 No issues starting when starting/driving car to first store. Car started without issue and I drove to next store a few minutes away. Came out of store to start car and got a notification on dash to check electric vehicle system. Checked app and had error P1A9096 Air Flap Turned car off for a minute, turned car back on and still received the same error. Tried to drive back to house (only about 6 miles away) and realized the car was limited to 25 mph although no indication/notification of limit. Notification continued and I ended up getting a stop vehicle and check electrical system with flashing lights. Stopped and cycled off and on the vehicle a few times. Started vehicle and only check electrical system notification was on (no indication not to drive vehicle so I continued driving). …

What failed: On February, 6, 2026, I experienced a complete failure of my Ioniq 5's electrical system due to the ICCU failing. Heard a loud "pop" and eight seconds later it reported a warning to check the vehicle's electrical system and 24 seconds after the pop it then chimed repeatedly saying to pull over immediately and come to a complete stop. The vehicle is currently at a nearby My safety: Once I was able to hobble the car off the side of the road, it left me in a dangerous situation. The vehicle was such in a state that the hazard lights were not operational and I had no way of getting any heat. (It was 20F with a wind chill down to 14F.) It also happened in a bad part of town, meaning that I did not want to leave the vehicle unattended for a tow truck. This also occurred 60mi from home. …

During a family road trip, my 2025 Hyundai Ioniq 5 (~9,000 miles, less than one year old) suddenly showed red "Check Electric Vehicle System" and 12V battery warning lights and then completely lost power. The 12V system failed entirely - the vehicle could not be driven or shifted, and the doors and the rear hatch could not be locked or unlocked. It had to be flat-bedded to a Hyundai dealer because it was completely inoperable. The dealer diagnosed a failed ICCU (Integrated Charging Control Unit) and a blown ICCU safety fuse (fault code P1A9096) and is replacing both under warranty; the component is available for inspection. The ICCU converts high-voltage battery power to charge the 12V system; when it fails, the vehicle loses all electrical power and drive capability. The warning lamps appeared immediately before total power loss, with no prior symptoms at the last scheduled service. …

I was slowing down, actively pressing the brake pedal to bring the vehicle to a full stop. As the car decelerated to what my senses and perception registered as a full stop, I pressed the "P" (Park) button while keeping my foot on the brake pedal. I felt the physical click of the "P" button under my thumb while still holding the brake, and my mind registered that the vehicle had successfully transitioned into Park. Before turning around, I visually confirmed that the vehicle had come to a complete stop. Believing it was fully secured in Park, I turned my head to check on my child in the back seat and naturally released the brake pedal completely. However, the system had actually rejected my command. …

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. …

I leased a 2025 Hyundai Ioniq 5 with the exact same issue. The VIN is [redacted] My new Hyundai Ioniq 5 is having the same problem again! Vehicle will hesitate/shudder and pulsate at highway speeds. Between 57mph and 78mph seems to be where I can feel it the most. This happens on all drive modes and with or without brake regeneration turned on or off. Nothing seems to make it worse or better. Here is an example. If you are driving 65mph on the highway and holding your speed steady, the car motor feels like it's cutting in and out. Juddering forward and back. If you accelerate a tiny bit, it gets ever worse. It feels almost like the input signal from the peddle is choppy, causing the car motor to judder. It is a forward to back motion. Not a vibrate or side to side motion. Dealership said basically they'll keep the car and possibly we can hope Hyundai will lemon law me out of the car.

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. …

Transmission complaints in other Ioniq 5 years