2024 Hyundai Ioniq 5 Transmission Problems

Owner reports

Selected complaints filed with NHTSA by 2024 Hyundai Ioniq 5 owners, lightly cleaned up (personal details are redacted by NHTSA).

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. …

The vehicle was returned to me after a manufacturer-authorized high-voltage battery replacement that was completed on December 10, 2025. Immediately after pickup, the vehicle began exhibiting safety-related issues. I experienced abnormal and hard steering operation, repeated low coolant warnings, and battery management system (BMS) and electrical warning messages. These warning messages appeared immediately after the repair and before the vehicle was driven by me. I returned the vehicle to the dealership multiple times for the same issues. During the final visit, the dealership retained the vehicle for approximately 12 days. After this inspection period, I was informed that the vehicle had underbody damage affecting the coolant system and high-voltage battery and that the damage was likely caused by road debris. …

On the morning of [redacted] 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 ([redacted]) After doing research online I found this to be a common issue with Hyundai/Kia EV vehicles. …

According to Hyundai, all active recall campaigns have been addressed on this vehicle (NHTSA site says it wasn't, Hyundai claims it was on 9/22/2025). Last night (3/3/2026) while driving on an unlit, two-lane country road about 20 minutes from my house, I heard and felt a bang noise from underneath the rear cabin of the car accompanied by a message stating "Stop vehicle and check power supply" on the dash. The car immediately went into a limp mode, reducing speed to ~40mph. After about 0.5 miles, the car further reduced speed to about 25mph (in a 55mph zone). As speed reduced further (no indication of what the speed would be reduced to), I pulled the car off of the road and awaited tow service. As this happened in the evening on an unlit country road, I was forced to wait for assistance along a stretch of road that could have been hazardous. …

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 . …

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 …

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. …

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. …

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.

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 [redacted] 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.

Transmission complaints in other Ioniq 5 years