The ICCU on my Ioniq 5 failed about a year after getting the software update that supposedly addressed the issue. I am very concerned about the reliability of my car going forward as it doesn't appear Hyundai has addressed the issue and I have no reason to think the replacement ICCU component won't fail as well.
2023 Hyundai Ioniq 5 transmission complaints
Page 2 of 4: complaints 11 to 40 of 72, newest first, as owners wrote them.
Having the same ICCU Failure that all other Ioniq 5 owners have. On February 26th, I was heading to work when I heard a pop and car displayed warning lights saying check EV system and stop safely. Car was limped home and towed to dealer. Was told fix will take a month.
During level 2 AC charging the circuit breaker in the house tripped. Tried again on a level 1 charger that came with the car and again it tripped the home circuit. Again, the car overloaded the house electricla system to a point it tripped the circuit breaker. Car taken to dealership for repairs. Dealership trouble shooting identifed failed ICCU with burnt connecter pins. HyundaiCase Management number 42152269 THIS IS A FIRE HAZARD FOR THE CAR AND HOUSE.
First time this occured we were driving in the winter and the car randomly shut down and started saying "Electrical Fault" or something of the sort. Turns out it was an ICCU issue. We got this replaced last year. Turn around 6 months later and the same thing happened again, but in an intersection. From my understanding when the ICCU fails the entire car basically goes into limp mode and prevents you from driving. Super dangerous and very hard to trust moving forward. Both of these issues have been confirmed by the dealership.
Had an ICCU failure that prevented the car from being able to drive.
While driving, the vehicle displayed a “Check Electrical System” warning and experienced loss of propulsion power. The vehicle became inoperable and required towing. The Hyundai dealer diagnosed failure of the Integrated Charging Control Unit (ICCU), a known failure point on this platform. The ICCU is currently on backorder with no confirmed repair date. This failure creates a serious safety risk, particularly if it occurs at speed or in traffic. I no longer feel the vehicle is safe or reliable to operate.
High-voltage battery system failure causing complete loss of propulsion. Vehicle entered "turtle mode" (reduced power warning) at 25% charge, then became completely immobile — unable to move even on flat surface. This has occurred multiple times. Charging system displays "fully charged" within one minute while vehicle dashboard shows 60% — clear battery management system malfunction. Vehicle has been undriveable and awaiting battery replacement for over a month at this point with no information on when the battery will arrive or be in stock. This is a known widespread defect in Ioniq 5 vehicles. Multiple owner reports document the same battery system failures, extensive reports of ICCU failures, and Hyundai's solution is to replace these failing components with the same component that fails repeatedly in other vehicles. No permanent fix or design change has been issued. This is a critical safety defect. Vehicle becomes completely immobile without warning — total loss of propulsion in traffic creates immediate crash and stranding risk. False charge readings mean the vehicle cannot be trusted to complete any trip safely. I have been left stranded multiple times on the turnpike of 80mph speed limit due to sudden total system failure. Hyundai has not resolved the root cause. They continue replacing batteries with the same defective system. This vehicle is fundamentally unsafe and unreliable. I should not be required to drive a vehicle with a battery system documented to fail catastrophically and repeatedly. Service records and repair invoices available upon request — vehicle currently at dealer awaiting battery replacement.
After having service done for the past two ICCU recalls months and months ago, I’m driving along today and hear the loud pop that everyone else reports. My car immediately went to a reduced power state where I was able to limp a bit further until I lost all power. I had to have the vehicle towed (by a wheel lift/dolly equipped wrecker - do not allow a flatbed they’ll drag your car into the truck) to the nearest dealership and now await to hear how long I’ll have to be without it.
ICCU failed while at highway speeds (65mph). Car went into 'turtle mode' limiting the car to 10mph. No warnings were provided prior to the incident. I was in the left of three lanes and had to make emergency actions to get to the Right shoulder across traffic. Traffic was obstructed. Was left stranded until a tow truck was available. Dealer confirmed ICCU failure.
While stopped at a stop light, "check electrical system" warning flashed on instrument panel without any prior warning or malfunction. I was only able to move the car about 50 feet before all power and controls failed. I was in a middle lane and was barely able to move the car out of traffic. Tow truck driver with a large jump start battery pack was able to give it enough power for me to crawl it onto their flatbed, my small lithium jumpstart pack was only enough to get the rest of its doors unlocked. Battery temperature was about 30 degrees F, state of charge 75 percent, had been driving from home less than 10 minutes, car had been sitting outside for a few days. Problem diagnosed as ICCU failure by dealer service department, now waiting on replacement part to complete repair.
While driving my 2023 Ioniq5 I got a warning on the dashboard about losing power and immedately the car slowed itself down to about 15 MPH, once I was able to get to a safe spot to pull over I stopped the car and it would not start again. I had it towed to the dealer and it has been a week and the ICCU is still on backorder. No idea when I will have the car back.
The car had no power on Monday [XXX]. It was taken taken to Tasca Hyundai in Hartsdale NY. The service manager told me it was the ICCU and 12v battery. This had previously been repaired on 12/11/24 under recall according to Hyundai's own records. The current service manager has no idea when the part will be available, possibly not for weeks. The car has been serviced according to Hyundai's maintenance schedule and recall notices. In fact the car went for maintenance one week prior to the part failure. No recall notice for this failure has been issued INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Vehicle experienced sudden loss of power while driving at highway speed. While driving on the interstate at highway speed in dark, snowy, high-traffic conditions, the vehicle displayed a warning about an electrical system fault and instructed me to “stop safely.” The vehicle immediately lost some propulsion and ramped down speed. We were only narrowly able to exit the highway before it would not move further. We were very lucky that no one hit us- it is extremely unsafe to drastically decrease speed on highway. Our family was in the car and it was very, very scary. We were able to use the heating system while parked for a few minutes before we lost all power completely. The vehicle was towed to a Hyundai dealership and is completely inoperable. The service manager stated the failure is consistent with a known ICCU (Integrated Charging Control Unit) failure. The dealership reports having many Ioniq vehicles with similar ICCU failures awaiting backordered parts, with no estimated repair timeline.
Upon entering vehicle in the morning of 12/30/25, a notable smell was first present. After turning on the vehicle, the car dashboard showed a "Check electric vehicle system" warning. The car was not able to be put into any gear besides neutral. Car was towed to dealership, and received word on 1/2/26 that an ICCU failure was the cause.Thankfully this occurred while parked in my garage, so was not in immediate danger. Perhaps this isn't a safety issue, but I am not sure what would have happened had the ICCU blown while driving so thought worth reporting.
Car gave an error check electrical system and went into limp mode on highway slowing to 25mph.
I purchased my Hyundai Ioniq 5 on [XXX]. Since then, I have experienced repeated and dangerous failures of the air-conditioning system, which Hyundai and the selling dealership have failed to properly diagnose or repair. On [XXX], while driving, I heard a very loud banging noise coming from the front passenger side of the vehicle. Immediately afterward, the air-conditioning system completely shut down and stopped producing cold air. Before the extreme Arizona heat began, I repeatedly asked Hyundai on Bell Road in Glendale to properly diagnose the A/C system due to ongoing concerns. Despite the vehicle being under warranty, the technician told me I would have to pay a diagnostic fee before they would evaluate the A/C. As a result, the underlying problem was not properly diagnosed or repaired. On [XXX], the exact same failure occurred again the same loud banging noise followed by a complete loss of air conditioning. The vehicle was taken to Hyundai on Bell Road in Glendale a total of four (4) times, spending 33 days out of service for the same issue. Despite this, the dealership failed to repair the vehicle. On several visits, the car was simply parked, and the dealer later claimed it had been “fixed” one time, even though the problem continued. This defect created a serious safety hazard. During one incident, while driving the vehicle in extreme heat to the dealership for repair, the interior temperature became dangerously high. My phone overheated and shut down, and I nearly passed out while driving. Hyundai Corporate has been unresponsive and dismissive. Rather than addressing the repeated failures and safety risks, I was referred to Lemon Law, where my claim was denied, despite the extensive repair history and time out of service. Instead of repairing the defect or taking responsibility, both the dealership and Hyundai Corporate pressured me to trade in the vehicle and move on, without resolving the underlying problem. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
INCIDENT DESCRIPTION: On November 24, 2025, while driving at ~60 mph on NYS Route 17 (highway) with ~15% battery charge, my 2023 Hyundai IONIQ 5 suddenly entered limp mode and lost motive power. The high-voltage battery state of charge dropped instantly from ~10-15% to 0%, triggering error code P1B9600 (HV battery cell imbalance—cells failing to charge/discharge properly). I was unable to fully remove the vehicle from the roadway. My elderly mother was a passenger; a passing tractor-trailer came within 1 ft of striking us when disabled. NY State Police responded (report available). Required $300 tow to the Hyundai dealer, stranding us 150 miles from home.//PRIOR RELATED FAILURES: 1. November 14, 2025: Stranded due to ICCU failure (recall 24V‑868 related) (stranded on NYS State Route 444). 2. September 15, 2025: Same P1B9600 code/limp mode/power loss; stranded in the middle of active travel lane of NYS 444; NY State Police report filed. 3. August 2025: Initial HV battery-related sudden power loss; stranded on Interstate 90 Eastbound (Erie, PA area). Despite repairs (September 2025 ICCU/"limp mode" software updates; October 2025 ICCU/high-voltage fuse replacement under recall 24V‑868), defects persist. The vehicle charge rate also appears low and the battery consumption rate seems high.// CURRENT STATUS: Dealer (Vision Hyundai) confirmed high-voltage battery pack defective, requiring full replacement. Vehicle purchased new October 2024, under warranty. In service since mid-November 2025 (>30 days downtime). Provided loaner now, but prior rentals unreimbursed.//SAFETY RISK: Repeated sudden power losses create extreme highway crash risk, especially with vulnerable passengers. I am a licensed professional mechanical engineer, and can provide technical logs, repair orders, police reports upon request.The issues I have experienced appear to be linked to ongoing ICCU/HV system issues in IONIQ 5. I respectfully request expansion of the recall investigation.
ICCU Failure — Severe Safety Risk and Repeated Incident The ICCU in my Hyundai has failed twice. Both times, the car suddenly and completely lost power while I was driving — no warning lights, no gradual slowdown, just total loss of control. This created an extremely dangerous situation that put me, my passengers, and everyone around us at risk. When the ICCU fails, the vehicle shuts down instantly and becomes completely inoperable. During the most recent incident, I spent more than eight hours on the phone with Hyundai attempting to arrange a tow. When the tow truck finally arrived, the driver instructed me to shift the car into neutral. The moment I did, the car died again and became stuck in neutral, preventing the driver from towing it. He then left, unable to assist, leaving my disabled vehicle parked on a public road — on a hill — where it posed a further safety hazard. Hyundai’s response to these failures has been temporary at best. This issue continues to reoccur, making the vehicle effectively unsafe to drive at all times.
the federal safety agency Vehicle Safety Complaint Vehicle Information: Year: 2023 Make: Hyundai Model: Ioniq 5 VIN: [XXX] Mileage: Over 137,000 miles 15 States Driven: AZ, TX, GA, CA, MI (with damage here primarily) Complaint: My 2023 Hyundai Ioniq 5 has experienced persistent and severe safety failures since delivery in January 2023, including: Complete power and control loss at highway speeds Repeated BMS/12V failures (even at 30% state of charge) Nonworking rear brake lights at night for over one year False-alarming and nonfunctional parking sensors Interior wear faster than normal; more These failures have created life-threatening hazards for me and my children, who regularly ride in the vehicle. The vehicle is under an active federal safety recall, which under 49 U.S.C. § 30118–30120 requires dealers and manufacturers to repair recalled vehicles promptly, without regard to profitability or cost. Despite repeated written requests, Pedder Hyundai (Poway, CA) refused to perform recall repairs, obstructed resolution, blocked corporate contact, and threatened to tow the vehicle illegally at my expense within 48 hours, demonstrating reckless disregard for consumer safety and federal law. A police report documenting criminal endangerment, conversion, and aggravated consumer endangerment is pending, and the lender of the vehicle has been notified of breach of contract. These issues appear systemic, affecting multiple vehicles of this model, and have resulted in: Frequent, unexpected towing with surprise expenses and downtime Significant risk of injury or death due to power/control loss Repeated failures despite warranty and recall obligations I request the federal safety agency investigate immediately, ensure recall repairs are completed promptly, and take any action necessary to protect public safety. Available case file including Dealer correspondence showing obstruction refusal threats to ignore California and federal law INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Had all previous open recalls for iccu performed. No previous warning in car. Driving unto free way. Loud noise like a tire pop. 12 volt low power warning on dash screen. Car began to lose power. Picture of a turtle shows up. Low power warning. Car lost power within 10 seconds. And couldn't accelerate. Extremely dangerous. Once completely stopped the car turned off and couldn't start again. Was able to get car to turn on with jumper cables by tow truck. But couldn't get to "start" engine. Dealership says the 12 volt battery and iccu needs to be replaced. They are blaming the issue on the fact that I had an aftermarket subwoofer installed and don't want to cover under warranty. Car ran fine with said subwoofer for a year prior with no additional changes. Have used same subwoofer and amp on multiple cars with no issue.
My vehicle displayed a Check Electrical System failure warning and experienced a complete loss of electrical power. Since it is an electric car, the car would no longer run. No light including emergencies lights worked. This happened to me in my driveway. But it happens to other owners driving down the freeway and they suddently have to pull over. Hyundai advised me to have the car towed to the dealership service center where they diagnosed an ICCU failure. This has been happening to to 2-5% of Kia and Hyundai electric cars. I was told the ICCU was on extreme backorder. I waited ~6 weeks for my car to be repaired. Note that there were two recalls for the ICCU unit previously and I performed those recalls promptly. There were no other warnings at all before the Check Electrical Systems error and sudden loss of power.
The ICCU failed which prevented the car from moving. ICCU was replaced by dealer under warranty. Had to be towed from the roadway.
Vehicle warning alarm came on with message to immediately pull over and check power supply. Towed car to dealer where ICCU and fuse were replaced. This after 1-2 recalls were completed.
My car’s ICCU (Integrated Charging Control Unit) failed, causing the 12-volt battery to stop charging and die, leading to a loss of power to the vehicle, resulting in the vehicle being completely immobile. I was driving on a busy road when all of a sudden the car started to slow down dangerously which almost caused the cars behind me to crash into me. The car's screen said it was entering limp mode. Then the vehicle completely stopped. I was stranded far away from home. I had to call a tow truck to tow the car to the dealer. The problem was confirmed by the dealer. The dealer confirmed the ICCU and 12-v battery failed. The dealer took 3months to repair the car.
The car lost its ability to accelerate during rush hour on a very busy interstate while I was in the far left lane. It started by jerking really hard off and on, like a very hard brake for a second, and then normal for a few seconds, and then hard braking again. I could accelerate after the "braking". There were no warnings or errors. This continued for about a minute while I was trying to decide if it was triggered by accelerating or braking, and I couldn't figure it out. At that point, I couldn't accelerate and received a number of lights and a message to check the EV system or the electrical system. I don't remember because at that point I was trying to immediately figure out how to pull over and not get hit. Luckily, it was slow enough and traffic had just thinned out enough, having passed a popular exit, so that I could coast to the shoulder across all of the traffic. I noticed at this point that the car was in neutral. I couldn't shift into drive, however. I tried to see if turning it off and back on might help. It did at that point. There were no error messages, and I could shift into drive and drive normally after turning it off and back on. Again, I wasn't concerned with documenting an error message that I assumed would be stored. The car is available for inspection. The safety of myself and my kids and other drivers around me was at risk as we could not accelerate and I was in the far left lane to the right of an express lane and left of a lot of traffic to have to cross to get out of traffic. No, the problem has not been reproduced, and it was taken in the next morning to the dealer who found nothing wrong and no stored error codes. No lamps or messages appeared before the loss of acceleration and promptly disappeared after restarting the car. Nothing was stored for the dealer to retrieve, either. The dealer ran diagnostics and found nothing wrong.
Code P1A9096 Iccu and fuse. The car is currently at a dealer in Barre, VT. While driving numerous warning lights appeared lowering my speed to 10 MPH immediately leaving me vulnerable to a collision in moving traffic. Warning lights include "Check Vehicle Electric System", "Power Limited". Issue confirmed at dealer.
2023 Hyundai Ioniq 5 ICCU failed with DTC P1A9096 which renders the vehicle in limp mode once the 12V battery drains. This is a major issue which keeps happening even after severals recalls with software updates related to this problem. When this incident happened i had gotten all the recalls and software updates available for the entire care and still it failed prematurely at 35K miles.
One month ago, my car experienced an failure and the warnings on the dash reported to check the electrical supply and then to stop driving the car immediately. I had it towed to a dealership who reported the ICCU failed and it'd take 1-2 weeks to get replacement parts and repair. A month later, I was just told the part is on indefinite back-order and they have no ETA when a replacement part will be available. Hyundai is selling an unsafe vehicle without that can die on the road and have no way to fix the issue. Google "Hyundai ICCU failure" and you'll see this is a systemic problem and Hyundai is doing nothing to fix these issues and is putting out 2025 models that are dying on the road with no solution.
Vehicle stopped responding to all inputs while cruising on the highway. Vehicle was charged and running fine up until that point, for about 40 minutes of continuous driving. Accelerator pedal, regen paddle shifters, cruise control buttons all would not work and display was unresponsive. Vehicle slowly lost speed as if it was shifted into neutral, forcing us to pull over to the side of the road. Turning vehicle off, waiting for a minute, and turning it back on restored functions. Vehicle malfunction occurred right after a busy intersection on LA highways and we were able to make it to the shoulder, but if it had happened just 1-2 minutes earlier, we would have been in a lot of traffic merging in and out of lanes at significant speeds. There were no warning lights, messages, or auditory alerts during the occurrence. Vehicle simply lost all power. When I took it into the dealer for inspection the next day, the service staff were unable to find any issues or errors during diagnostics. Battery health was in the green and vehicle checked out fine and was released to me after a thorough inspection.
While reversing slowly, I heard a "pop" noise (sounded like balloon popping) from the rear of the vehicle, and within 15 seconds later, a "Check Electric Vehicle System" warning appeared on the dash alongside the check engine light. About 5 minutes later, I received another warning that said "Stop Vehicle and Check Power Supply" and noticed the car was losing power. Was able to get it home to get it towed, but this was within 2 months after receiving the ICCU recall for this vehicle, and it seems the ICCU has failed again.
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