Owner-reported complaints naming the powertrain system, filed with NHTSA
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Powertrain reports that are not specifically the engine or transmission — driveshafts, axles, transfer cases and differentials. Every record below is an owner-reported complaint about the 2025 Hyundai Ioniq 5 submitted to NHTSA — not a confirmed defect, not a recall and not a manufacturer bulletin. 56 reports on file name it.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
The 25 most recent of 56, in the owner's own words
I started the car and got the warning "check electric vehicle system." The car then lost power. It would only go 27mph with the accelerator pedal pushed all the way to the floor. My safety was at risk because my car was not responding appropriately to driver input. The car is at the dealership as it is undriveable in this condition. This is the second incident with this vehicle within 6 months.
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 assume that the vehicle likely still had a small amount of speed at the exact millisecond I pressed the button, and the computer automatically blocked the “Park” command and kept the car in gear. Because an electric vehicle operates in almost complete silence, with no engine noise or vibration to indicate that it is still in gear, there was no auditory or physical cue to alert me that the car was moving when I released the brake. While my attention was turned toward the back seat for a few seconds, the car quietly began to creep forward, leading directly to the collision with the car in front of me. Following the accident, I found that the vehicle produces slightly different sounds when Park is rejected and when it is successfully engaged. However, the owner’s manual describes only the dashboard message and does not describe these sounds or explain how to distinguish them, so their meanings may be learned only through the failure. At the time of the incident, I was not familiar with the distinction between these two sounds. Because my brain processed the physical press of the button as a successful action, and I had visually confirmed that we were not moving, my focus immediately shifted to my child. I was entirely misled by the digital interface.
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. This is a known, safety-critical failure on this platform: a sudden, complete loss of power can strand occupants and, if it occurs while driving, cause loss of motive power - a serious crash risk. My vehicle was stationary when it failed, but the same failure at speed would be extremely dangerous. I have video evidence of the car completely bricked out.
Vehicle was parked in closed garage overnight. In the morning I tried to start the car and it was unresponsive. key fobs, digital keys, NFC cards none of them were able to open the car. Used a physical key to open the door, and then tried to turn the car on, nothing worked all screens remained black and car was unresponsive. AAA confirmed that the 12V battery was fully dead. When they jumped the vehicle we heard a pop in the car, which is a known ICCU failure indication. The car still turned on and was drivable. I got it to the dealership safely and they confirmed that the 12V battery was fully dead and car only turns in if jumped. They also confirmed that the ICCU had a failure as well and they are going to need to replace the entire battery pack/ICCU assembly.
Car charged as scheduled overnight 3/28/26 but was dead the morning of 3/29/26 and when it was jumped gave error "Battery overheated, please stop and exit vehicle" and "check electrical system" - vehicle has been in shop for 16 days, no diagnosis except that it "probably" needs a HV battery.
On April 1, 2026, my 2025 Hyundai IONIQ 5 experienced a cascading electrical failure. The vehicle first displayed a warning about a problem with the on-board charger, followed shortly by an alarm and the 'Stop Vehicle and Check Power Supply' warning with a red 12V battery indicator, rendering the vehicle unsafe to drive. Had I been on the freeway this would have been extremely dangerous. My Bluelink diagnostics history confirms three fault codes from that date: P1A9096 (ICCU fault, Electric Vehicle / Air Flap system, still Open as of 4/3/2026), and P056216 (Voltage Regulation fault, Hybrid Control system, reported twice), consistent with a cascading ICCU failure causing 12V system collapse.
Car showed electrical problem on the dash. Car would not start.
ICCU unit of the car short circuited right in middle of driving and caused the car to go in "limp mode". Sudden pop noise and slowdown created situation where car could be rear-ended. The part has already caused recall for prior model years, but model year for my car is not included in the recall. Based on internet search it is a continued and widely prevalent issue, manufacture has not done enough to fix this and a recall needs to add new model years. Additionally, the parts are backordered and there is no immediate fix.
I started driving and pulled out of a parking lot onto a busy road. The ICCU had failed unknownst to me and as I was underway the car started losing power and the dashboard lit up with warnings about the electrical system. I was limited to 25 MPH for a brief time and struggled to turn off into a parking lot amongst much faster traffic. While doing this the car slowed further to 10 MPH. I limped at this speed into the parking lot at which point it turned off and lot all power. This happened over the course of about 30 seconds. If it had happened on a busier road I would have been in trouble. On the highway and it would have been extremely dangerous. It was dangerous enough as is with cars passing me 20+ MPH faster than my car could go. This all occurred with no warning, and is due to an issue with the ICCU in the car that Hyundai has known about for years and has refused to address or fix.
ICCU fuse blew during operation, car went into limp mode. Vehicle is currently being serviced under warranty through Hyundai
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 ICCU (and the associated fuse blew) while I was driving and it caused the car to be slowed immediately to approximately 20 MPH. This apparently is a huge issue with this 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.
While attempting to leave home, the 'Check Electrical System' warning came on. The vehicle entered a 'safe mode' and was unable to accelerate. The car was towed, and the dealer confirmed a complete failure of the ICCU and associated fuse (DTC P1A9096). This is a known issue (Recall 24V-204) and created a dangerous situation.
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.
The ICCU failed under normal utilization The vehicle went into limp mode which changes expected driving dynamics The dealer confirmed ICCU failure and the manufacturer has confirmed the vehicle is a lemon as per MA state law No warnings prior to the failure
ICCU failure at 5308 miles. heard a loud pop while driving and 12v warning system errors
ICCU confirm dead by the dealer. IONIQ 5 2025 AWD. only had this car for 5 month, 4900 miles. vehicle stopped at the middle on the highway. luckey, no accident occur. no part avilable, no ETA for fix, no loaner from dealer.
ICCU failure causing the vehicle to be inoperable
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.
Main battery failure, can not charge, can not drive car. Warning light(s) on dashboard. High voltage battery needs to be replaced.
Vehicle experienced a dashboard alert, "Check electric vehicle system." The car produced an OBD code: P1AD3(00). Upon taking it to the dealer, they determined that the EV required a new high-voltage battery.
ICCU needs to be replaced.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Categories with enough reports to have a page of their own
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