2025 Hyundai Ioniq 5 Transmission Problems

Your car's ICCU (Integrated Cluster Control Unit) short-circuited while you were driving, causing the engine to enter "limp mode" with a sudden pop noise and significant slowdown. This created a dangerous situation where another vehicle could have hit you from behind. Although this part has been recalled for earlier model years, your 2025 model year isn't included in that recall, and replacement parts are currently backordered with no immediate solution available.

Your car's integrated control unit (ICCU) failed without warning while you were driving on a busy road, causing sudden power loss and multiple electrical system warning lights. Your vehicle slowed dramatically from normal speed to 10 MPH over about 30 seconds, then shut off completely in a parking lot. This loss of power while surrounded by faster traffic created a dangerous situation that could have been much worse on a highway.

Your Integrating Charging Control Unit (ICCU) failed while you were accelerating onto the highway, causing your car to enter 'Limp' mode and limiting your speed to 20 mph—a dangerous situation with highway traffic moving at 60-70 mph. Your car displayed both a battery warning and overheating symbol, indicating the battery overheated. Hyundai has recalled this same component in 2022-2024 Ioniq 5 models, but your 2025 model was not included in that recall despite experiencing the identical problem. The fix will likely involve replacing or reprogramming the charging control unit.

Your car's dashboard displayed an electrical warning, and the vehicle wouldn't start. This appears to be an electrical system issue that may have prevented the engine from cranking. The problem may require diagnosis of the battery, electrical connections, or starting system components.

ICCU fuse blew during operation, car went into limp mode. Vehicle is currently being serviced under warranty through Hyundai

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 failure causing the vehicle to be inoperable

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.

Main battery failure, can not charge, can not drive car. Warning light(s) on dashboard. High voltage battery needs to be replaced.

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.

ICCU 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.

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. Reproduced: The dealership it was towed to is not open until Monday, February 9, 2026 but the tow's rescue battery made the system run enough to report the Diagnostic Trouble Code of "P1A9096". Doing a quick search online for that shows a number of cases with the same problem. While waiting for the tow, I tried to start the car a number of times to no avail. Inspected: Not yet, see "Reproduced" section above. Any other signs/symptoms? Nothing until the "pop" itself. Once that happened, basically every warning icon showed up on the instrument cluster/screen.

2:27 pm on 02/06/2026. Pop heard from the trunk area, then displayed "Stop vehicle and check power supply," the car lost power and then became completely immobile. The car has 3500 miles on it. Bluelink app showed "Everything looks good."

ICCU failure

I was at the grocery store and when I returned to my car and started it, I had an error message on the dashboard regarding the vehicle battery. When I put it into reverse, I heard a loud pop and received another error message. The car would only drive at 25 mph after that. I tried to drive home but the car died after a few miles and I was stranded at the side of the road. It was towed to a dealership and I have been told that it is an ICCU failure. At this point, I have been waiting 3 weeks for it to be fixed.

The car is a brand-new 2025 Ioniq 5 with only 2,949 miles. All of a sudden and without warning, it entered "limp mode" while driving and did not go past 25 miles per hour. I was close to home so luckily I was able to street park it safely. Called roadside assistance and the car completely powered off (died) in front of the tow truck. The dealership says it is an ICCU failure and need to be entirely replaced. The part is backordered with no ETA for replacement.

On [XXX], the vehicle was unable to be started - no lights, no power, unable to open the doors. I called Hyundai Roadside Assist and they sent someone from AAA a few hours later who was able to "jump start" the vehicle. I took it to the dealer, Manly Hyundai, on December 17th, 2025 and they determined nothing to be wrong with either the battery or the electrical system. On [XXX], while driving from home to the local grocery store, the car presented a warning light on the dash and the “gas pedal” stopped working. I was able to coast into a parking lot at which point an even larger warning light appeared and the vehicle then lost all electricity completely. I again called Hyundai Roadside Assist and they sent someone from AAA a few hours later who determined that the car was unable to be “jump started” and would have to be towed to the local dealer, Manly Hyundai. The dealer reported back to me that the component that failed is called an “ICCU” and is some kind of controller related to the charging and motors of the electric drivetrain. It is available to be inspected at the dealer currently, Manly Hyundai. My safety was put as risk because the car became essentially inoperable while driving downhill and gave no warning signs ahead of time before the lights lit up on the dash and I lost control. The dealer has confirmed that it is an issue with the “ICCU”. The dealer has inspected the component at their service department. The first warning light that appeared came at the same instant that the vehicle lost drive power. The second warning light that appeared came at the same time that the vehicle lost all electricity entirely. There were no indications that something might be wrong with the vehicle prior to the vehicle actually producing symptoms of being undriveable. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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). Continued driving and heard what I believe was a pop noise and also got the notification to stop vehicle and check system. Pulled over turned vehicle completely off and checked app again. and Still only PA9096 error. Contacted Hyundai roadside. Truck driver contacted me shortly after letting me know they were on the way. Tried to turn vehicle around in parking lot so easier to tow. Vehicle limited to 1 mph. Vehicle died when I got in spot and wouldn't turn back on. Vehicle towed to dealer. 1/28/26 Over a week after issue, dealer diagnosed as ICCU and fuse failure.

On 1/15/2026, my 2025 Ionic 5 Limited AWD car with 11K miles on it suddenly lost power about 1/2 mile from my home. I pulled over to the side of the road and within seconds the car was totally dead (nothing worked). After waiting 1 1/2 hours (in an unheated car with outside temperatures in the 30's (F)) the car was towed to the dealership, where the ICCU was determined to be the problem. The dealership apparently has 3 other Ionic's waiting for new ICCU's. My car has been in the shop ever since, waiting for the replacement ICCU to be delivered to the dealership (delivery is apparently expected sometime in the next couple of weeks).

ICCU failure. Vehicle was not able to be operated over 40mph creating significant safety risk.

The ICCU in my Hyundai Ioniq 5 failed catastrophically today ([XXX]) after only 3109 mlles. I believe this to be the case because: • I heard a loud pop from behind me in the car. • The car immediately lost power and would only go very slowly. • An alert about the electrical system immediately came on and told me to stop driving as soon as possible. • A rather loud alarm sounded. • DTC P1A9096 appeared in my Bluelink app. All these point to a failed ICCU. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ICCU failed. ICCU fuse blew limiting power making car unsafe to drive.

While driving in traffic I heard a loud pop coming from the rear of the vehicle. A warning light came on on the dash board and the vehicle immediately slowed to about 10 mph. This was a dangerous situation as I was actively passing a vehicle on the highway and could have ended up colliding with oncoming traffic!

As I was driving on a very busy city street I heard a loud pop and then got a warning to check electrical systems. Luckily I was able to get the car to a Walmart parking lot and arrange for the car to be towed to a dealer 90 miles away. The dealer contacted me and informed me the ICCU unit and high voltage fuse would have to be replaced and no time frame for parts availability to be determined. This is apparently a recurring problem with the ICCU component of Hyundai electric vehicles that could potentially leave a driver stranded in the middle of nowhere in the middle of winter.

On [XXX] 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. They stated: 1) No recall exists for this issue and claim this is only impacting 1% of vehicles. 2) The supply of ICCUs was depleted in December 2025 and have been on backorder since. 3) There are no plans to redesign the ICCU to prevent failures so this could very well happen again, and as there are no indicators as to what causes it to malfunction it is making the vehicle unreliable. They have 'escalated' this but I likely will not get the vehicle back for a few more weeks. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The ICCU failed with only 5,000 miles driven. The car then lost power, and would not move. Luckily, I was in a residential area. Had I been on the highway, I am uncertain if I would have been able to safely pull off to the side of the road.

Vehicle is approximately 8 months old, has 9390 miles on odometer. While on a road trip, we stopped to charge the vehicle at a DC fast charging site. After about 10 minutes of charging, there was a loud pop sound and the vehicle stopped charging. Attempting to unplug and replug the charger into the car gave nothing but an error. Contacting support, was told that the vehicle has an air flap problem. That is not the problem. The charge controller system (ICCU) failed during charging, leaving the vehicle without power to charge the 12V battery system, and only enough driving power to limp 1 mile to a hotel. Vehicle required towing 400 miles to get to home dealership for repairs. Hyundai reps have stated that this 2025 vehicle is not part of the ICCU failures recall, but it is obviously exhibiting the same problems. I no longer have confidence this car can be driven any significant distance from home, which ruins the functional value of the vehicle.

Vehicle unexpectedly entered reduced-power mode while driving. Speed was limited to approximately 25 mph and vehicle displayed “STOP VEHICLE AND CHECK BATTERY” warning along with master warning light and battery warning. MyHyundai system logged an active air flap fault. Vehicle was not drivable and required flatbed tow to dealer. This created a traffic safety risk due to sudden loss of power and inability to maintain safe speed.

Was driving shortly after starting the car and heard loud pop. Immediately received notification that I there was a problem with the electrical system. Received DAT code P1A9096. Car is undrivable. Had to pull over to side of the road and call for tow.

I am reporting a serious safety defect involving my 2025 Hyundai Ioniq 5 (lease vehicle, brand new). While driving on a highway in Massachusetts during snowy conditions, the vehicle suddenly displayed a critical warning message “Stop and Check Power Supply” and lost power, forcing us to stop on the highway. There were two children in the vehicle, and the situation was life-threatening due to traffic speed, weather conditions, and lack of a safe shoulder. The vehicle is new and under lease, and this type of failure is unacceptable and extremely dangerous. The car had to be towed to Hyundai of Braintree, MA. This is a serious safety failure, not a comfort or convenience issue. I am concerned this defect could result in serious injury or death if it happens again, either to my family or to others. I am requesting a formal investigation into this defect.

I was driving on the freeway in the left lane when suddenly a bunch of error lights popped up on the dash and the car threw itself into neutral. When I tried to give the car acceleration it wouldn’t go which is when I realized the car was in neutral. When I tried to go into drive it did not go so I turned the hazard lights on. Turned off the car, turned it back on and then again all the error lights popped up. I went into drive and when I drove a loud bang noise happened in the rear and after a few feet the car went into neutral. I repeated the process trying to merge from the left lane into the middle where finally the car would not even go into drive anymore. I then called 911 and had them tow the car off the freeway while I waited inside. Car had 3400 miles, was only a few months old (brand new) and I had 60% battery left with almost 200 miles of electric range left. It was a sunny day with no moisture recently.

The ICCU unit failed causing the car to first have low power, reducing the maximum vehicle speed to 25 MPH, then causing the 12V battery to lose charge making the car inopperable.

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. I was extremely fortunate to be so close to home when this happened - from what I know of the issue, had we been stranded on the highway with this issue we would likely not have been able to use the HVAC systems in the vehicle for long. At this point, the issue has been diagnosed at the dealership as an ICCU issue which is covered by warranty. I have not been told to modify anything about my charging amperage, and there has been no admission that the ICCU part itself is faulty (though I believe it must be - my vehicle has less than 8,000 miles and the previous model years of Ioniq 5 all had ICCU recalls already.)

I was leaving from a friends' house and got a "Check electric vehicle system" error and the car went into "limp" mode while on the road. I drove to a hotel parking lot and dropped off my family then proceeded the next day to drive the car to a local dealership for service and the car maxed out at 12 mph before crawling to 1 mph while going up a hill before I could find a place on the side of the road to stop. While awaiting a tow truck the car's electrical system fully "died" leaving me stranded on the side of the road without even hazard lights to warn surrounding traffic. The problem has not yet been evaluated by a dealership, manufacturer or any other agencies. Several warning lamps and messages appeared, including the "Check electric vehicle system" error message.

My car worked to get to an appointment on 22 Nov. It flashed an error 2 minutes into a 20 minute return trip, saying the cars propulsion failure was imminent. Vehicle would not turn back on after the 3 mile drive home. The ICCU failed. If this failed while driving, or while I was in a hot/cold location, my life and those around me would have been at risk. The dealer has been working with Hyundai America for a month to fix the vehicle, and so far has not been able to after trying 2x replacement parts.

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. This can be confirmed from the numerous posts and videos online (YouTube, Reddit, Ioniq forums, etc.). Given that ICCUs continue to fail at a significant rate, resulting in reduced vehicle speed and vehicle shutdown within minutes (as soon as the 12 V battery is exhausted), I strongly urge NHTSA to do the following: 1. Consider the current ICCU software update to be an ineffective remedy for recall 24V-868. 2. Broaden the scope of recall 24V-868 or create a new recall for all Hyundai/Kia/Genesis eGMP platform vehicles to address this defect. 3. Require that Hyundai/Kia/Genesis create and deploy a truly effective remedy for this defect.

EV battery failure. This is a known issue that Hyundai is refusing to acknowledge is a common problem on their cars.

Was driving for 12 miles, at a stop light. Light turns green, I accelerate, loud collision warning goes off and warning “battery overheated! Pull over safely and leave the vehicle”. Could not pull over safely because the car immediately ceased and locked up, car behind me nearly rear ended me and swerved to avoid. Is this another ICCU unit failure? Car towed to dealership (car has 2056 miles in it, it’s practically new) and been there for almost a month now with no repairs done and still diagnosing the problem. This car is unsafe.

On the first snowy day of the year, the car experienced an apparent ICCU failure. Loud pop followed by warning lights, reduced power and eventual complete shutdown of the car. Car has been towed to dealership for diagnosis and repair.

I heard a "pop" and then immediately saw "check electric vehicle system". The code I'm receiving in the app is P1A9096. The car was limited in driving speed, and I managed to get the car to the dealer before it stopped driving completely. I have about 8000 miles on this <1 year old car, and it seems like the ICCU has fried. Hyundai says this is under 1% of all cars, but from the internet it seems like this happens way more frequently. Reporting to the NHTSA so that there's record of this happening, given the frequency it seems to happen on the internet and the paucity of solutions (beyond putting in another faulty part) from Hyundai.

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. I took the car to the dealership where they confirmed they could feel it too. They ended up rotating my tires... Said that's all they can really do because Hyundai doesn't have anymore information. They basically said sorry but they can't help.

I leased a 2025 Hyundai Ioniq 5 with the exact same issue. The VIN is [XXX] 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. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)