2024 Hyundai Ioniq 5 Transmission Problems

Your car displayed multiple "Check Vehicle Electric Systems" warnings while driving, then when you restarted it and shifted into drive, you heard a pop from underneath and the car entered a limited "Turtle Mode" with warning lights. The vehicle then completely lost power, leaving you stranded in freezing weather without the ability to lock the doors or open the trunk. The dealership diagnosed the problem as a faulty ICCU (Integrated Charging Control Unit) that required replacement.

Your car displayed a "Stop vehicle and check power supply" warning while driving and then became completely inoperable, requiring a tow to the dealer for an Integrated Charge Control Unit (ICCU) replacement. The owner reports that a previous recall did not resolve this issue and that multiple Ioniq 5 vehicles continue to experience sudden power loss on the road.

While merging onto the highway, your car displayed an electrical system warning and shut down completely within 20 minutes, requiring a tow to the dealer. The dealer identified that the Integrated Cluster Control Unit (ICCU) needs to be replaced. This sudden loss of power while driving poses a serious safety risk, especially in heavy traffic or on busy highways.

Your car's Integrated Charging Control Unit (ICCU) has failed, which controls the charging system. This appears to be a recurring issue that Hyundai hasn't fully resolved yet. The fix will likely require replacing the ICCU module with a newer version or software update.

Your car suddenly made a loud bang noise from underneath the rear cabin and displayed a "Stop vehicle and check power supply" warning message on the dashboard. The car then went into limp mode, progressively reducing speed from 40 mph down to 25 mph despite being in a 55 mph zone, forcing you to pull over on an unlit country road. This happened about 5 months after Hyundai performed recall work on the vehicle, and the dealer hasn't yet determined what caused the problem or how long repairs will take.

Vehicle displayed "Power limited" and slowed to a crawl, was able to drive less than a quarter mile to a safe place before it displayed "Stop vehicle and check power supply" then completely shut down. Diagnosed as ICCU failure by the Hyundai Dealer service technician, with the parts on backorder and no ETA for the 15 or so other Hyundai Ioniq 5's with the same failed ICCU waiting at the same dealership, in front of me.

The car stalled while being driven by my son. It displaced an error code. The Car had to be towed to dealership. It was diagnosed with ICCU unit failure. Needs to wait over a months for parts.

“Check electrical system” warning while driving. Sudden loss of power and speed. “Turtle mode” icon. Limped home 2 miles at <10mph. Vehicle bricked. Towed to dealership.

ICCU failure: confirmed by dealership, submitting for your records - while driving the morning of 2/11/26 in Evansville, IN a warning message appeared on the dashboard stating 'Check Electric Vehicle System' followed by a rapid deceleration. Luckily there was not a vehicle behind me as they would have rear ended me. This failure occurred without warning and presented a significant safety hazard, leaving the vehicle stranded in traffic until I was able to restart it. Vehicle went in to turtle mode upon restart, would not go over 20mph at first then I stopped the car, restarted it again, it would move for 15-20 seconds before going in to turtle mode again and now it will not go over 10mph - interestingly, when I would stop and put it in reverse, the vehicle would move 10-20' and then come to a very abrupt stop as the entire vehicle shut off - had to tow the vehicle to the Hyundai dealership in Evansville Indiana where the ICCU was confirmed has having failed

Multiple 12v batteries, the battery management system, and ICCU have all failed on my Ioniq 5. During my 13-month lease, this vehicle has been inoperable for more than 30 cumulative days due to the same recurring defect. The vehicle was taken to an authorized Hyundai dealership multiple times, but the defect was repeatedly misdiagnosed and not corrected, resulting in continued failures and extended loss of use. The defect causes sudden loss of power and complete vehicle shutdown, including the inability to restart the vehicle. If this occurs while driving, it creates a serious safety hazard by eliminating propulsion, power-assisted steering, and braking assistance. The vehicle may become disabled in traffic or at intersections, increasing the risk of a collision, injury, or stranding occupants in unsafe conditions.

On January 1st 2026 around 11am we were traveling in rural Wisconsin when we heard a loud pop from under the back seat . This we now know from Dahl Hyundai in LaCrosse was the ICCU failing . When this happened we were in blizzard conditions and the car forced us into limp mode and reduced us from 55 mph down to 25mph in bumper to bumper traffic on a rural hwy (this was not a smooth speed transition the car performed ) We drove the vehicle back to the nearest town going 25mph as it was alerting us that we were on limited battery as this issue in short time will make the vehicle inoperable . We found a safe place to stop and did so. We called Hyundai Roadside assistance who then let us know it would be 9 minutes until we received help. This would actually take 4 more hours . They left us with a car that did not operate , produce heat in a blizzard . We eventually had family pick us up so we were safe . We still do not have the vehicle back as Hyundai America has the part (ICCU) on back order with no ETA of repair. .

On the morning of [XXX] I received an error message on my dashboard (attached) "Stop Vehicle and Check Power Supply". The car had started to lose acceleration power to no more than 30MPH. I contact the service department at my local dealer. They instructed me to bring it in or have it towed. I was about 2 miles from home so I headed back. While in transit the car lost all power in the middle of traffic. It stopped completely ! No emergency flashers, lights, power for the doors, windows, etc. I could not even put into Park. If I lifted my foot off of brake, it started to roll backwards. Luckily I was not on the expressway or at a railroad crossing. Fortunately a local police officer saw my dilemma and directed traffic and pushed my car to the side of the road ([XXX]) After doing research online I found this to be a common issue with Hyundai/Kia EV vehicles. The ICCU fails with no warning leaving drivers stranded.. The unit is on backorder because of so many failures and there is no ETA INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Warning light came on stating that we needed to have the electrical system checked asap. Vehicle would not charge from Level 2 charger. It needed to be towed from our house to the dealer to get its ICCU replaced since there was a risk that it would no longer power vehicle on 4 mile drive to dealer for repair. Problem was fixed in one week by Roseville Hyundai by replacing the ICCU in the vehicle

12 volt battery drained in my driveway on 1/20. Vehicle was completely dead including door and hatch locks. Roadside assistance jumped the 12 volt battery. Vehicle message said, “Insufficient power. Check Electrical system”. Vehicle was towed to local Hyundai dealer, who diagnosed an ICCU failure. The dealer has four other Ioniq 5s with the same problem. Replacement ICCU is on back order with no ETA for delivery. There were no warnings prior to the ICCU failure. If the vehicle were being driven when this failure occurred, the loss of power would have put all occupants at great risk.

The ICCU failed at 11,000 miles and 11 months into the lease. When the ICCU fails, the car becomes inoperable. This was a major safety hazard since it broke down on a major US highway and I was barely able to get off to the side of the road. This seems to be affecting a large number of Ioniq 5 and Ioniq 6 models.

What component or system failed or malfunctioned, and is it available for inspection upon request? - It was ultimately diagnosed as an ICCU failure. The part is no longer in my possession. How was your safety or the safety of others put at risk? - Occurred on public street, fortunately a slow moving 25MPH speed limit several blocks from my workplace. I was able to limp the vehicle to a nearby parking lot and call for towing. Unfortunately, several hours later the vehicle was unable to be moved, leaving me stranded, and requiring it to be towed to local Hyundai dealership. I was ultimately without a vehicle for >1 week. Has the problem been reproduced or confirmed by a dealer or independent service center? - Yes, confirmed as ICCU failure. Additionally, my vehicle had the software update at the time that was supposed to fix / greatly decrease the rate of ICCU failures. I had no outstanding recalls on the vehicle. Vehicle was ~1 year old and had less than 12,000 miles on it. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? - Yes, at least local Hyundai dealership mechanics Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? - Initially the error message "stop vehicle and check power supply". The next day, that message, then a yellow turtle and "Power Limited"

While driving, I heard a loud pop in the rear passenger side and subsequently, the dashboard showed an error to "stop vehicle and check power supply". After driving about 15 minutes, another error showed on the dashboard "12V battery voltage low. Stop safely". After coming to a stop, the vehicle completely shut off and would not turn back on. A tow truck was called and my vehicle was towed to a Hyundai dealership. The vehicle is now at the service center at a Hyundai dealership. The dealership confirmed it was an ICCU failure. While there was not a crash or any injury, the known defect from Hyundai left my wife, my [XXX] daughter, and me, stranded 60 miles away from home, in the middle of the night. Luckily we were pulled over safely and not in the middle of the highway. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The ICCU failed while driving. A loud pop occured then a red warning light came up asking you to stop the vehicle and check the power supply. The car went into turtle mode where I could at best drive 25 miles per hour. This car was part of a recall last year to prevent this issue, however only a software fix was performed. Luckly I was able to get the car home on a very cold day.

The vehicle is less than 1 years old. Had 91% charge left. Turned in the car as usual. Turned in heated seats and heated steering wheel as the outside temp was 34 degrees. A pop noise occurred and my entire dashboard flashed like a Christmas tree saying electrical system failure. Pull over safety. The cars speed was reduced to 20 mph. This was extremely scary as this happened on a main road where the speed limit was 55. The ICCU failed according to the dealer. This has been a common issue among Ioniq5 cars and the manufacturer has failed to fixed this issue. This car presents a high failure rate of the ICCU computer that controls the entire car. Once this chip fails, the car can not be driven and it must be towed back to the dealership. This is not a one off. Hyundai also quietly remove the remote start feature to activate the heated seats. They must know that turning on the heated seats might trigger an overload causing possible risk of iccu failure.

When I started driving my car a warning to check the electrical system came on the display and the speed of the car dropped to less than 25 mph. The road we were driving on was over 45mph without a safe shoulder. After it was towed to the dealer, they diagnosed that the ICCU had failed and replaced it and a fuse. This was after all recalls and other software updates were performed many months ago.

My 2024 ioniq 5 has no recall but they have a well known issue where the ICCU does not charge the 12v as expected. this results in loss of power. In my situation, i was driving on the freeway at 65MPH when i got the low 12V battery message and my car slowed down and I was not able to accelerate at even street speed. I was fortunate enough to pull the car over from the left lane to the right shoulder as the traffic was light. This could have easily resulted in an accident. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While accelerating onto a road with cars approaching from behind, vehicle entered limp mode and was restricted to 25 MPH. I was forced to leave the roadway to avoid a collision with the vehicle behind. The street this occurred on has a speed limit of 40 MPH. The vehicle's normal acceleration was sufficient to ensure a safe gap to the approaching car, but the time it took to recognize and react to the unexpected behavior reduced this gap. The dealer diagnosed this as an ICCU failure related to safety recall 272. All prior recalls were complete at the time of the incident.

ICCU failure, resulting in 12v discharge and complete immobilization of car. The car's safety systems gave sufficient warning to allow me to get somewhere safe -- but the nature of the failure also disabled it's ability to maintain a call with blulink to coordinate a pickup. Luckily my cell also had service.

I was driving 10-15km/h over speed bump suddenly my car going backwards I took a glimpse on my display panel and it showed that the car was in D mode. This is seriously can cause accident!

I had ICCU software recall done in spring 2025 then Vehicle died twice while driving on highway, ...suddenly. "warning 12 volt batt low pull over" stranding my family twice on highway. could not operate anything. Mc Govern Hyundai said it was fixed after 44 days. 2 days later failed again .dealer said it was ok again but would not replace ICCU or 12v batt. the amber light that indicates when !2v batt. is being charged would never come on. they said they found nothing wrong.

Dear NHTSA, On [XXX] at [XXX] CST, my 2024 Hyundai Ioniq 5 SEL experienced a sudden ICCU failure. While reversing into my driveway, I heard a loud “pop,” followed by warning messages: “Stop vehicle and check power supply” and “Check electric vehicle system.” A DTC scan showed code P1A90(96). The car became inoperable and had to be towed to a Hyundai dealership. The dealer confirmed ICCU failure and replaced both the ICCU and fuse on 6/17/2025. However, the replacement was not a redesigned part—it was the same model that failed. I purchased this vehicle in March 2025 as a Certified Pre-Owned with ~12,000 miles. All recall-related ICCU updates had been completed before this incident. There were no warning signs before the failure. This failure could have been dangerous had it occurred on a highway, in extreme weather, or far from help with my [XXX] daughter with me. I no longer feel safe driving this car. Hyundai’s recall remedy is clearly not effective, and they continue replacing defective ICCUs with the same flawed units. They have not disclosed the root cause or implemented a permanent fix. I urge NHTSA to: Investigate ongoing ICCU failures despite recall compliance. Mandate a stop-sale of affected vehicles until a real fix is found. Require Hyundai to disclose the root cause. Consider a buyback program if no safe solution is available. This is a serious safety risk. These failures will continue without regulatory action. Sincerely, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ICCU (Intergrated Charging Control Unit) failed after two mandatory recalls were completed. Vehicle is not drivable as it’s awaiting for a replacement ICCU (backordered). Replacement ICCU will not remedy the issue since it has not been improved upon from the original failure. Vehicle shutdown on a two lane highway with a 65mph speed limit. The section where the vehicle shutdown was without cellular service and on a bend with no shoulder, which increased the risk of an accident. The problem was reproduced in other vehicles using the same part. The component has been inspected by the manufacturer and dealer with a temporary remedy of replacement. Warning lights appeared after the failure occurred; essentially giving the driver no warning or time to react. The vehicle displayed a warning message to pull over and turn off vehicle immediately. Power was reduced to 15mph for about 15-20 minutes.

ECCU failure unexpectedly failed while driving . Failure occurred on busy road, car went from being able to drive to suddenly complete stop from the vehicle with no warning. Car was not able to restart after failure. Dealership confirmed ECCU failure

Error message indicate loss of charge capacity. Car slowed down, with enough range to pull off the road. Dealer indicates the integrated charge control unit (ICCU) failed, and quit charging the 12 volt system. Waiting for parts (1 month so far). Seems like the same issue reported under NHTSA recall 272 for the Ioniq 5 Does Hyundai have a list of failed ICCU’s, and whether there might be a batch of these units that are failing, or is this just a random occurrence?

The Integrated Charging Control Unit (ICCU) failed while I was driving to work. I was on the highway in the middle of a blizzard and the "Check Electric Vehicle Systems" warning popped up on my dash. It then when into a turtle mode and my car would no longer go above 15 - 20 mph. I had to exit the freeway very abruptly because my speed was dropping quickly. It was already extremely dangerous driving that day, this just added on top of it. It is available for inspection, it's been sitting at my dealership since March 6th because the ICCU is back ordered and there is no ETA when one will become available. The dealership has inspected and confirmed it is a faulty ICCU. There were no other problems with the car until the warning appeared on the dash. The ICCU has had 3 manufacturer recalls for the ICCU previously. Which I have gone in to the dealership for.

About 2 minutes after I started driving, I got a "Stop Vehicle and Check Power Supply" warning. The car slower to about 20 mph and would not go any faster. After returning home, I had the car towed to the dealership. Hyundai said that the ICCU unit failed. This was days after the same dealer performed recall work that was supposed to address ICCU issues.

Started car and proceeded to drive to work. 1 mile from home, heard a "pop" noise and the car displayed "Check Electric Vehicle System" warning and went into a "turtle" mode that limited speed. Luckily I was on a side street and had not yet made the turn onto the main highway or it may have obstructed traffic or resulted in a crash. I was able to return home and have the car towed back to a Hyundai dealer for diagnosis and repair. The dealer identified the issue as the ICCU fuse and ICCU itself that needed replacing. All previous recalls and software updates were completed, including the latest ICCU recall (272?) which was completed on December 3. There have now been multiple software updates and recalls targeting this part, but it still resulted in the vehicle losing power and being inoperable.

Our 8-mo old 9800 mile Ioniq 5 failed to maintain its 12v battery while parked for a week. It was dead when we came back to it. Jump started successfully. I replaced the OEM battery with an AGM battery, which the car failed to maintain charge on after 2 weeks. At that time, while driving, the car displayed "Stop vehicle and check power supply" and "check vehicle electrical system." I had a battery monitor installed which showed the car only had 44% charge left in a new 12v battery. By the time we made it to the dealer 15 minutes away, the car was barely above 20% on its battery, and was about to stop on the road. The car has been diagnosed with an ICCU failure and replacement parts are 2+ months backordered. This car appears to brick itself without much warning to the driver -- and clearly Hyundai's software-only recalls are not fixing the root cause of this dangerous safety issue.

When driving in i-Pedal, which is a "one pedal driving option", sometimes after pausing the car rolls backs several inches. This appears to be a defect with the powetrain, regenerative braking engine, or otherwise. Hyundai's dealership has been advised of this issue; they have escalated this internally. A car in drive forward should never due to electrical or software reasons be told to move backwards -- which is what is happening here.