If you’re in the market for a new or used Hyundai Ioniq 5, the most popular of the E-GMP-based EVs, there’s a high chance that you ran into the following acronym: ICCU. And those four letters may evoke dread.
The acronym stands for Integrated Charging Control Unit: a nifty piece of hardware that bundles all the charging controllers, current converters and power export bits into a single unit.
It’s a powerful piece of equipment, but it can fail—specifically the part that charges the 12V battery. That alone isn’t a huge issue. The low-voltage battery can go bad in any car, including combustion cars, if the alternator doesn’t do its job properly. In the case of the Hyundai Ioniq 5 and other E-GMP-based EVs, the driver is made aware of things going south by a “Power Limited” warning that appears on the digital instrument cluster. Then, the car gradually loses power until it can no longer move, making it a tow-truck kind of situation.
While failures seem to be relatively rare as Hyundai, Kia and Genesis’ E-GMP sales have taken off, these high-profile incidents that have left often-new EVs “bricked” have caused extreme trepidation among owners. And while there have been recalls to fix the issue, some drivers have reported still experiencing ICCU failures after the repairs were done, too.
According to the chronology report published by the National Highway Traffic Safety Administration (NHTSA), drivers should be able to drive the vehicle for up to 45 minutes after the warning pops on the display. But here’s where things get complicated.
Hyundai has issued two recalls to fix the issue in the United States, with the most recent one in November. According to the NHTSA documents, a total of 145,351 EVs in the U.S. are part of the recall, including the 2023-2025 Genesis G80, 2022-2024 Hyundai Ioniq 5, 2023-2025 Genesis GV70, 2023-2025 Genesis GV60 and 2023-2025 Hyundai Ioniq 6. Additionally, there are 62,872 Kia EV6 vehicles from 2022-2024 included. Similar recalls have been issued in other parts of the world, too.
The ICCU is tasked with a lot. It handles DC fast charging and AC charging and it makes sure the 12-volt battery is up to spec. It’s also responsible for the vehicle-to-load feature, allowing owners to export power from the high-voltage battery to tools, or appliances or even their homes via an adapter that plugs into the charge port.
As per the recall report, the ICCU failure has two causes—overvoltage induced at the start and end of the 12V battery charging cycle and from thermal loading during charging and/or driving. When it fails, it’s because a transistor inside the ICCU goes kaput and pops the fuse that feeds energy into the 12V battery.
To fix the issue, a service bulletin states technicians will first scan the vehicle to check if the diagnostic trouble code (DTC) P1A9096 is stored in the car’s brain. If it’s not there, they’ll move on to updating the ICCU’s software and call it a day. If the code is stored, then the ICCU and the fuse—even if it has not blown—will be replaced, and the low-conductivity coolant will be flushed. The ICCU software will also be updated.
As spotted by MotorTrend, the software update changes the way the ICCU makes use of the high-voltage battery to charge the 12V battery, and, more importantly, it forces the low-voltage DC-to-DC converter to do a “soft start” when charging the low-voltage battery. This, according to Hyundai, reduces the overvoltage that’s mentioned as one of the causes of the failures. Furthermore, the new software changes the way the fans and water pumps operate to make sure temperatures don’t get too toasty inside the ICCU.
Statistically, just 1% of the roughly 200,000 vehicles involved in the recall can have their ICCUs fail, which is 2,000 cars. Out of all the cars that are part of the latest recall for the failing ICCU, 41,137 Hyundai and Genesis EVs have already been fixed by Jan. 22, while another 14,828 Kia EV6s have had the remedy applied. Motor Trend concurred in a recent look at the issue: “It’s a big deal, but not one that individual E-GMP owners are statistically likely to face.”
This doesn’t mean that all these cars have had their ICCUs replaced, though. As we mentioned earlier, if there’s no trouble code, then just a software update is needed.
However, if you ask owners who have had their cars die on the highway, things are not exactly rosy. Some drivers claim that they had the ICCU fail on their EV before having the recall work done. Then, after fixing the car and updating the software, a second failure occurred.
“Second ICCU failure, first one [was] replaced seven months ago,” said Reddit user beyondthetech. “Luckily I wasn't vacationing down at the Jersey Shore last time it happened. Nevertheless, knowing they're just replacing them with the same built, unimproved ICCUs meant that it could fail again just as easily, and seven months later, it did.”
Another member of the Ioniq5 subreddit had this to say about their experience: “I am taking my car into the dealership tomorrow, but it looks like I have a SECOND ICCU failure on my hands with my 2022 HI5. First one was June 2024 while 600 miles away from home. So less than a year ago. Absolute nightmare of an experience.”
For some owners, getting their cars fixed took weeks or even months.
“I’m beyond fed up with Hyundai,” said Danki13. “My late 2021 IONIQ 5 has been in the shop more than it’s been on the road, and the latest fiasco has pushed me over the edge. I’ve been waiting FIVE MONTHS for them to replace the ICCU (Integrated Charging Control Unit). Five. Months.”
We got in touch with Hyundai to try and find out what owners can do to mitigate the chance of the ICCU failing on their vehicles, regardless of whether the recall was already done. A Hyundai Motor America representative said: “The best course of action is to have the remedy performed.”
That’s a hard pill to swallow for people who have gone through Hyundai’s service department twice for the same problem, leading owners to question the quality of the fix and whether the 1% failure rate is even accurate.
We asked Hyundai if there are statistics available regarding the actual number of EVs that had their ICCU fail after getting the recall, but we received no response. So the best information at hand is what has already been published by the NHTSA, which states the vast majority of affected vehicles will be fine.
Subjectively, people who have had bad experiences with cars tend to voice their woes loudly, whereas happy owners don’t go to the trouble of writing about their experience. “With the two recalls to address the ICCU and then the subsequent failure, I don’t have faith in the vehicle or faith Hyundai has a grasp of the situation,” one self-labeled “ICCU victim” said in a Reddit thread.
Have you had issues with this component on your Hyundai, Kia or Genesis EV? Get in touch: tips@insideevs.com.
