2023 Hyundai Ioniq 5 transmission problems

POWER TRAIN

I have a 2023 Hyundai Ioniq 5 Limited and had the ICCU "popped" (failed) which took about two weeks to replace. This time we were lucky that in happened at our home but had we been driving the car would it would have completed died. We regularly drive from from [XXX] to [XXX] were there are large section of [XXX] with no cell service. Meaning potentially walking for miles in extreme heat or cold. Hyundai right now seems only interested in continuously replacing the part rather than actually fixing the route cause, making it so the car is not trustworthy or safe to drive long distances. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11747025 — an unverified report by a vehicle owner.

POWER TRAIN

Car indicated 12v battery was critically low and that I should stop safely. I was just starting it in a parking lot. This is a classic ICCU failure and the car is up to date on all recall updates. The car requires manual key unlocking for outside access at this point, and the rear hatch is only unlockable using the manual release mechanism which is recessed into the rear hatch and needs the key. The back two doors cannot be opened at all, from either direction and the handles don't work when the electrical system has failed and the child lock was engaged accidentally when it happened. This legitimately terrifies me for anyone traveling with back seat passengers who need quick exit. There isn't one.

NHTSA complaint #11739646 — an unverified report by a vehicle owner.

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The ICCU died a second time

NHTSA complaint #11738416 — an unverified report by a vehicle owner.

POWER TRAIN

ICCU failed at 20,000 miles, 2 years after I first got the vehicle. Blue link showed the P1a9096 ICCU code failure. Car could not be driven for more than a few minutes then the message to stop safely came about and car would die. It took the dealer 2 months to replace the ICCU with the SAME defective part. It is only a matter of time before it fails again.

NHTSA complaint #11734215 — an unverified report by a vehicle owner.

POWER TRAIN

My Hyundai IONIQ 5 has repeatedly lost 12V power and shut down. The vehicle had to be jumped by AAA multiple times. After being restarted, it died again, and after two days of use it was dead again. I am concerned this is related to the known ICCU / 12V battery charging issue affecting IONIQ 5 vehicles, which can cause loss of motive power or make the vehicle undrivable. The vehicle is currently at Hyundai Southern States in Raleigh, NC for diagnosis and repair.

NHTSA complaint #11733953 — an unverified report by a vehicle owner.

POWER TRAIN

There was sudden power reduced and turn to the limp mode(Turtle symbol popped up). After pull over my vehicle to highway shoulder, the vehicle became total power loss. Unable to drive anywhere. It was a dangerous situation for my family. We waited tow car and took my vehicle to Hyundai dealership which located close to my house. They diagnosed my car and after a day. They told me it needs to be replaced a ICCU assembly and Fuse. There was no ETA for the parts. They provided me a loaner’s car. After about 15 days, they fixed and I was able to take my car.

NHTSA complaint #11730155 — an unverified report by a vehicle owner.

POWER TRAIN

On 11/7/25 , we were driving my 2023 Hyundai Ioniq 5 to a friend's home in rural [XXX] , a trip of approximately 160 miles. At around 5:00 PM, we stopped about halfway to our destination to charge the battery. The car would not charge above 47%. While we continued to attempt to charge the battery, the console displayed a Check Electrical System Warning message, and we received the DTC P1AA700 via BlueLink. We were concerned about our safety on the drive up to the mountains. We were afraid the car would stop running on the highway and cause an accident. We were also concerned the car would die in a remote area and we would be stranded. However, the dealership was closed for the weekend. We drove carefully to our friend's home. I contacted Stevens Creek Hyundai on 11/10/25 and arranged to bring the car in on 11/11/25. It had 13,652 miles on it at that time. Eventually, the dealer confirmed the DTC P1AA700 and said they would need to order a new EGMP battery. The car was in the shop for 128 days, waiting for Hyundai to "build a battery" in [XXX] . Eventually, Stevens Creek Hyundai replaced the EV battery and I picked up the car. Given the delay in repairing my car and the growing evidence of Hyundai battery failures, we wanted to report this problem to the authorities. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11729574 — an unverified report by a vehicle owner.

POWER TRAIN

While driving the vehicle, the ICCU failed. The vehicle shut down in the middle of traffic without any warnings.

NHTSA complaint #11729262 — an unverified report by a vehicle owner.

POWER TRAIN

ICCU failure, left stranded for a tow

NHTSA complaint #11725930 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11725456 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11721884 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11720012 — an unverified report by a vehicle owner.

POWER TRAIN

Had an ICCU failure that prevented the car from being able to drive.

NHTSA complaint #11716442 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11715970 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11715479 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11714617 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11713902 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11713951 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11713769 — an unverified report by a vehicle owner.

POWER TRAIN

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)

NHTSA complaint #11712858 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11712173 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11708407 — an unverified report by a vehicle owner.

POWER TRAIN

Car gave an error check electrical system and went into limp mode on highway slowing to 25mph.

NHTSA complaint #11707186 — an unverified report by a vehicle owner.

POWER TRAIN

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)

NHTSA complaint #11706715 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11706423 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11694439 — an unverified report by a vehicle owner.

POWER TRAIN

NHTSA 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 NHTSA 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)

NHTSA complaint #11693988 — an unverified report by a vehicle owner.

POWER TRAIN

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.

NHTSA complaint #11687016 — an unverified report by a vehicle owner.