2024 Hyundai Ioniq 5

Known ICCU issue: the 12v battery died for no reason rendering the car undrivable.

The issue involved a failure of the 12V battery system in my Hyundai Ioniq 5, which powers essential electronics and allows the vehicle to operate. The battery suddenly lost charge while I was driving, causing the vehicle to become inoperable. The car was towed to a dealership, and the battery and related systems are available for inspection. My safety and the safety of others were put at risk because the failure occurred on the road, forcing me to pull over unexpectedly. This created a hazardous situation, especially in traffic, as it increased the risk of a collision or leaving me stranded in an unsafe area. The vehicle has been taken to a dealership for diagnosis, they had stated there is a recall on this vehicle, iccu unit failed and needs to be replaced. It has been inspected by the dealership service department, but not by police or insurance representatives. Prior to the failure, there were clear warning lights or messages indicating an issue. The problem appeared suddenly while driving, within 5 minutes the car shut down.

For the second time, the integrated control unit, ICCU, has failed to this is AFTER being replaced under the recall. The recall solution has not fixed the problem, and is a fake bandaid on a problem that means cars will totally stop working in the middle of the road. This is totally unsafe and unacceptable.

On [XXX], my 2024 Hyundai Ioniq 5 experienced a sudden and complete failure of the Integrated Charging Control Unit (ICCU). The failure rendered the vehicle inoperable without warning, requiring it to be towed to a dealership. The vehicle is currently located at AutoNation Hyundai in North Richland Hills, TX and should be available for inspection upon request. This failure created a significant safety risk. The vehicle lost functionality unexpectedly, which could have resulted in a dangerous situation if it had occurred at highway speeds, in traffic, or in an unsafe location. A sudden loss of power or inability to restart the vehicle presents a clear hazard to both the driver and others on the road. Prior to the failure, there were no clear warnings indicating an imminent critical issue. A 12V battery issue was suspected at the time of failure, and roadside assistance replaced the battery, but this did not resolve the problem. The root cause was later identified as an ICCU failure. The problem has been confirmed by an authorized Hyundai dealership (AutoNation Hyundai, North Richland Hills, TX) on April 10, 2026. The dealership determined that the ICCU requires replacement, with an estimated minimum repair timeline of four weeks due to part availability. The vehicle has been inspected by Hyundai roadside assistance and an authorized Hyundai dealer. No inspection has been conducted yet by the manufacturer directly, law enforcement, or insurance representatives. This issue appears to be consistent with widely reported ICCU failures in Hyundai Ioniq 5 vehicles, suggesting a potential systemic defect that may warrant further investigation and possible recall action. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My on Thursday, April 2, my 2024 Hyunda Ioniq 5 displayed the "Check Electrical System" message displayed. I had just started the car. I started to lose propulsion on a busy street [XXX] ). I managed to get the car to [XXX] and had to pull over. I had the car towed to the Luther Hyundai, [XXX] . On Monday, April 6, the dealer informed me the ICCU failed. The ICCU and a fuse were replaced. I picked up the car April 7. Although Hyundai has supposedly fixed the ICCU problem, it continues to fail, as mine did. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Based on all symptoms - loud pop followed by limp mode and electrical warning, and inability to charge -- iccu is busted.

ICCU failure. Common problem but Hyundai seems to have no fix despite it happening for years now.

I was driving at 25 mph when I heard a loud pop come from the rear of the car and subsequent warning message came up on the dashboard - "STOP VEHICLE AND CHECK POWER SUPPLY". In an electric vehicle this is a very alarming message to see. I was fortunate to be close to home so I was able to drive home and call roadside assistance for my car to be towed to the dealer. The vehicle has since been diagnosed with an "ICCU" failure. I had no indication or warning that this was going to happen, just a sudden failure.

I was driving in a parking lot and heard a “pop” sound like a balloon breaking. The Ionic 5 lurched and stopped. A red circle appeared on the dash and said “check electrical system.” I slowly maneuvered the car into a parking spot because there was very little power and turned off the car. I called the Hyundai dealer and they told me to have the car towed to the dealer in Palm Springs, CA. When the tow truck unloaded the Ionic 5 at the dealer, I attempted to move the car into a parking spot so it was out of the traffic lane. I started the car again it again lurched and a yellow circle came up with a turtle icon. Then another red circle appeared “check 12V battery”. The car would not move after that. I went into the Hyundai service department and talked to the service representative. He said he would take the vehicle in for service and I signed the paperwork.

On 3/19/2026. Battery was at 20% SOC. Plugged in my home L2 charger. Car did not start. Took vehicle to dealer the next morning 3/20/2026. It was diagnosed as an ICCU failure. Parts ordered car left at dealer but still waiting on 4/9/2026 for issue to be resolved.

The vehicle experienced a sudden failure of the 12V battery while on the road. The car stopped completely and became inoperable. At the time of failure, there were no tail lights or proper warning indicators working, which created a very dangerous situation, especially in traffic. I was stuck on the road for about one hour waiting for a tow truck. During that time, other vehicles were honking and passing by, increasing the risk of an accident. The vehicle had to be jump-started before it could be moved. Details: What component failed: The 12V battery system failed unexpectedly. The vehicle is available for inspection upon request. Safety risk: Loss of power caused the vehicle to stop on the road with no tail lights, putting my safety and others at serious risk. Reproduction/confirmation: Issue was temporarily resolved with a jump-start, but this is a known issue reported by other owners as well. Inspection: The vehicle has not yet been inspected by the manufacturer or dealer after this incident. Warnings/symptoms: There were no clear warning lights or messages before the failure. The issue happened suddenly without notice.

While driving I received the infamous "Stop vehicle and check power supply" warning, and it was then inoperable, needed a tow to the dealer for ICCU replacement. I can't believe you terminated your initial investigation into this in 2023 because they did a recall (which my car received). That recall did not fix the issue. It is March 2026 and Ioniq 5 and other models with the same electric system are dying on the road at the same rate as before. There is a large percentage of failed cars, and every failure is dangerous. This is a huge safety issue, and is not receiving adequate oversight by the NHTSA.

I was merging onto the highway. I got a warning that I needed to check my electrical system. I was able to back down the highway ramp and park on a side street. Within 20 minutes the car was fully dead and AAA needed to tow it to the dealer. The dealer confirmed that the ICCU needs a replacement. My family is lucky this happened in a place we could safely get to a side street. Had it happened 5 minutes later we would have been stranded on the highway with 2 small children.

ICCU and its fuse blew randomly while reversing out of a parking spot. A warning light appeared on the dashboard saying "check electric vehicle system" after a loud pop noise came from the rear passenger side. The ICCU charges the 12V battery on board, and when the 12V dies the whole car dies, resulting in the car shutting down suddenly. It's a known issue with this model car. The service center confirmed the ICCU blew when they ran diagnostics.

ICCU failure while driving.

ICCU Failure. Vehicle underwent deal TSB for ICCU failure resolution prior to still failing months later.

Diagnosed ICCU Failure. Complete loss of power, went into "turtle mode," then told to stop car immediately and have it towed to the dealership. Vehicle diagnosed several days later as having an ICCU Failure.

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. Hyundai's claimed recall campaign work was performed on 9/22/25 with subsequent recurring failure about 5 months later. The dealer cannot confirm the diagnosis or offer estimates of repair time/availability until they see the car (currently scheduled for next week).

Car was acting normally. Suddenly, the car would not accelerate. I was on a small road with no place to pull over. Vehicle said to pull over check electrical system. At great risk to my life and the safety of my children, we managed to get to a safe spot before the entire vehicle shut down. We expect that this was a failed ICCU.

ICCU failure