Was driving in Bellevue, WA leaving a parking lot. Heard a "pop" sound, and immediately had a "Check Electrical System" warning come up on the dash. From previous experience in 2024, was aware this requires immediate dealer inspection, so started driving to the dealer 6 miles away. After less than a mile, lost most power but was able to drive slowly into an office parking lot. Called Hyundai Roadside Assistance who sent a flat bed tow truck to transport the car to the dealer. ICCU was replaced in May 2024 after similar symptoms. The current ICCU (which is likely the failed component) was in service for less than a year.
2023 Hyundai Ioniq 5 transmission complaints
Page 3 of 4: complaints 41 to 70 of 72, newest first, as owners wrote them.
My Ioniq 5 has encountered the renowned "ICCU" failure -- 35k miles in, 2.5-3yrs of ownership. I had a loud 'pop' noise behind my driver seat occur and then my vehicle went into limp mode. The ICCU failure is confirmed by the dealer, but the part is on massive backorder nationwide...
On March 20, 2025, my 2023 Hyundai Ioniq 5 displayed the error "Stop check vehicle power supply" and abruptly shut down during rush-hour traffic, leaving my young son and me stranded on a heavily congested bridge. Immediately, the car’s display went dark, doors wouldn't unlock, and the gear shifter was immobilized. With no emergency functions available, we were completely trapped. On a slight incline, I had to continuously hold the brake pedal to prevent rolling forward into increasingly aggressive traffic, making an already frightening situation terrifying for my child. Police arrived but struggled to assist preventing the car from moving. After several tense minutes, the dashboard briefly flickered back on, enabling me to unlock the doors. AAA identified a dead 12V battery, replaced it at my expense, but the critical error persisted, causing another complete shutdown shortly thereafter. The vehicle was towed to Hyundai of Bedford, where technicians diagnosed the issue as a failed ICCU and fuse, parts that are now backordered due to high number of vehicals having this same issue. Alarmingly, Hyundai plans to replace these faulty parts with identical models, despite my vehicle having completed all recall updates. This means the dangerous malfunction could occur again without warning, posing ongoing severe safety risks to my child, myself and those around use. This deeply traumatic event exposed critical vulnerabilities in the Hyundai Ioniq 5, especially dangerous for families, elderly drivers, or anyone caught in similar emergencies. The absence of functional basic safety measures left my son and me unnecessarily vulnerable. My trust in this vehicle and any thing using the same ICCU is permanently broken. Hyundai urgently needs reliable, redundant safety systems to prevent such life-threatening scenarios. Until then, we cannot feel safe or secure in these vehicles.
After all of recall software updates were applied the ICCU still failed with no warning beforehand and resulted in power and propulsion failure.
ICCU failure, loud pop sound and then a "Check Electrical System" then after a minute a turtle icon and the car slowed down and stopped on its own in the middle of a freeway. Hyundai towed it and waiting for repairs. This was highly dangerous stopping in the middle of the freeway with no control over the vehicle and fast cars driving by.
ICCU ASSY and Fuse had to be replaced as well as the 12 volt battery which failed a few weeks after. The car lost power on a main road 2/3/25 and we were just able to get into a parking lot. The message to check power supply came on and we lost power immediately. The 12 volt battery failed when I went to pick the car up from the dealership after they worked on the bluelink settings that had to be reconfigured a couple weeks later 2/25/25. I was lucky that I didn't have to be towed that time. I had just got into the car to leave and the warning message came on to check the power supply. My dealer service dept was wonderful. I have absolutely no complaints about them but I am angry that Hyundai is putting these same bad parts in the 2025 Ioniq 5 and we can't trust our car! We love this car and were planning to buy another one but will wait to see if Hyundai does the right thing and fixes this problem.
Charging system warning light (for 12volt battery) illuminated on left side of instrument cluster. Warning in center of panel said pull over and stop vehicle. Had vehicle towed to dealership and diagnosis was “failed ICCU”. Been at dealer going on 4 weeks
While running errands, my Ioniq 5 suddenly made a pop sound, and the dashboard displayed a “Check Electrical System” warning, followed by a loud alert and a message instructing me to “Stop Vehicle and Check Power Supply.” I was able to safely park in a lot and called for a tow. At that point, the car was still operable, but after being unloaded from the flatbed, it would no longer turn on. The issue was diagnosed as a failed ICCU, and I was informed it will take one month to receive the parts and complete the repair. Had this failure occurred on a highway or busy street, it could have been extremely dangerous. I am fortunate that it happened in a safe location.
On [XXX], I was pulling into my driveway when I heard a loud “clunk” and an error message came up on the dashboard saying “Check Electric Vehicle System.” I checked the 12V battery which was at 11.9 volts, so I first tried charging it with an external battery charger. However, the error message still came up, and when I tried driving on my street it was limited to 25 miles per hour, and eventually I got the error “Stop vehicle and check power supply” and the car slowed to a crawl. There was no warning prior to the failure. I had the latest ICCU software update recall performed at Capitol Hyundai in San Jose, CA on December 30, 2024. The next day, I had the car towed to Capitol Hyundai; a week later they diagnosed the problem as a blown fuse and ICCU failure. There is no estimate on when they will receive a new ICCU part to repair it. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
ICCU error, check power source error then all electrical in the vehicle went out. No power steering, no acceleration, anll screens went black, all recalls addressed.
While driving the vehicle on a local road at around 40 mph, check electrical system light came on and I heard a pop sound behind me. The vehicle would suddenly go no faster than 30 mph. Upon further driving, for additional quarter mile, it would drive no faster than 12 mph. I was able to very slowly drive it 1.5 mi back home. Once I arrive home, the vehicle was no longer operational. I confirmed that the 12-volt battery was at an extremely low charge and having the vehicle on would not charge the 12 volt battery. I believe the ICCU failed. I am waiting for Hyundai to further diagnose this.
Car stopped driving. got a check power systems error and car went into limp mode then stopped altogether
I was pulling into my driveway and I heard a "clunk" and then an error appeared on the dashboard saying "Check electric vehicle system." My 12V battery then died. After recharging the 12V battery with an external charger, the "Check electric vehicle system" message came up again when I started the car, and I could only drive a block or so before another message on the dashboard said "Stop vehicle and check power supply." I had the vehicle towed to a Hyundai dealer where it is waiting for them to diagnose the problem. I had all of the ICCU software update recalls performed on the vehicle before this latest problem occurred.
The ICCU failed, leaving the car with a Check Electrical System failure and ultimately cutting power to the vehicle, forcing driver to pull over and stop.
Our all-electric AWD Hyundai Ioniq 5 has an issue where the rear motor electric oil pump (EOP) overheats and ceases to function when the problem occurs, which disables the rear motor and effectively causes the car to become a front-wheel drive vehicle with a "hesitation" in the acceleration. This problem only occurs after a long time of high-speed driving and typically on a warm day (upwards of 70-80 degrees F). When the problem occurs, the rear motor ceases to function at all and only the front motor operates to power the vehicle forward. The acceleration is also impacted, such that when the accelerator is pushed, the car "hesitates" for 1-3 seconds before the front motor takes over the demand for power and "lurches" the car forward in a jerky motion. The symptom will last as long as the car is in an overheated state. However, if you pull the car over and let it rest for a period of time (undetermined), the rear motor will again operate normally until it overheats again. For us, this occurred once on a very hot day traveling approximately 50-60 miles on interstate travelling at speeds over 70 MPH. On another occurrence, it happened after driving the car about 200 miles (stopping for a lunch break in the middle), for about 4 hours. When this problem occurs in other cars equipped with RWD only, they lose all forward power in the car and coast to a stop even when the battery still has a charge. We've taken it to our local dealership for repair on Sept 12, 2024 (McGee Hyundai of Barre, VT) and they claim that there is nothing wrong with the vehicle. After researching the topic, I've determined it is the failing rear EOP must be replaced [XXX] and [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Failure of the Vehicle Power Supply system. ICCU failure. Car was alerting and would not go over 24mph. This is the result of a recall that I had already brought in the vehicle for in April, but they only performed a Pass/Fail test and at the time it "passed" so they didn't replace the ICCU and fuse that is required to be replaced. Two months later the car died, had to be towed and now has been at the dealership for two weeks already - 17waiting for the parts to come in. This is ridiculous because Hyundai is aware of this problem and is not fixing the issue, merely kicking the can down the road and then stranding owners for weeks without their vehicles. Unacceptable.
My Hyundai IONIQ5 suddenly lost power while I was driving it. I was only able to go 20 mph for a short period of time before it completely died. I had to have it towed
First indication something was going awry was when attempting to charge the car. Heard normal click indicating charge had started, but no audible announcement that charging had started. Car started throwing "Check electrical system," then power plummeted and became unresponsive to accelerator, followed by "Stop car. Check electrical system," then finally something like, "Battery is being discharged by external devices."** Car had to be towed about 60 miles to nearest Hyundai EV service center. Eight days later, I got a call from service saying that the ICCU needs to be replaced. They will update me once ETA of part is known.
The vehicle made a loud popping noise and lost motive power. Dashboard lit up with battery symbol and said to check electric vehicle system. Dealer service is certain it is an ICCU failure. The vehicle had the software update to “fix” the ICCU issue thousands of miles ago.
The car loses power, slows down dramatically, and will not respond to the accelerator pedal. This failure has happened twice. The first time I was driving at about 40MPH on a side street when the car started slowing down with no warning and limped along at about 20MPH. I could not get it to move faster so I put my flashers on and made my way to the side of the street, pulled off of the road and shut the car off. When I restarted the car it drove normally. I reported the failure to Hyundai and they had never heard of this happening. They kept the car for 2 days and couldn't replicate the problem. That was about 2 months ago. Yesterday, 3/4/24, I was on the freeway going about 74MPH using the smart cruise control. I had just changed lanes when the car lost power and I got the message, "Smart cruise conditions not met." My speed dropped to the low 40's as other cars were whipping past me. Even though I floored the accelerator I got no response. I started the flashers, made my way to the right lane and got off on an exit ramp. I pulled off to the side of the ramp, parked the car and turned it off. Once again, when I restarted the car it performed normally. This is very dangerous! I could have easily been rear ended by another, faster car on the freeway since I slowed down so quickly without braking lights lighting. I brought it back to the dealer again today and they have kept it to run diagnostics. I don't expect that they will find any problem this time either.
I heard a pop from the rear of the car and warnings came up on the dash. The vehicle was power limited and needed to be towed to the dealer. It was diagnosed as an ICCU failure and blown fuse. This was the problem supposedly addressed in Hyundai TSB 997 (the federal safety agency ID Number: 10240086). That service was performed on the vehicle in September 2023. We were lucky the incident occurred on a city street and not on a freeway or rural highway where the sudden loss of power could have been very dangerous. The software fix applied under Hyundai’s TSB clearly did not fix the issue.
Driver was moving forward into a space in a parking garage between two other vehicles. Driver had pulled most of the way in and was slowly inching forward. As the car came to a stop, it suddenly lurched forward, hitting a concrete wall. The collision warning system did not alert, and auto-braking did not occur. The car was in Regen Level 3, and Auto Hold was not activated. In the months prior to this, the car twice had a similar situation when coming to a stop at an intersection with foot on the brake, then suddenly lurched forward, nearly rear-ending a car in front. There was no visible damage to the concrete wall, and a police report was not made. Hyundai says they want to inspect vehicle, but have not done so after a month. It is easy to believe that this was driver error, but it absolutely was not. Car lunged forward and accelerated into a wall with only the brake being applied. All of these events have occurred after the Hyundai Ioniq 5 software update was applied on 26 Sep 2023.
Driving the vehicle on the highway for longer than 60 miles at highway speeds the vehicle goes into “power limited” mode and a turtle pops up on the screen. You are unable to accelerate the car and once this happens you have to leave the car off for at least 5 minutes and then not drive above 65mph again or it will keep happening over and over. After taking it to the shop Hyundai Corporate said we need to drive the car again to see if they had fixed it. Approximately 65 miles into the trip it happened again and this time I was almost rear ended and cars were swerving around me on the shoulder to avoid crashing into me. Hyundai is saying that they cannot reproduce the issue but they are not driving the car on the highway for more than 60 miles. The safety of not only myself and my family is at risk as well as other people on the highway behind and next to us. The vehicle is currently at the dealership and they said there are no error codes so they don’t know what’s wrong. The only warning that popped up said “power limited” with a turtle.
Driving on the freeway at approximately 70 mph, the car lost the ability to accelerate and started to lose speed. I had my foot on the gas but the speed was dropping. There were no warning lights, messages, or other alerts prior to the loss of acceleration. The screen remained on during the loss of acceleration but a phone call was lost. Safety at risk for obvious reasons. I was able to put hazards on and move to the left-hand shoulder. I turned the car off and on again and was able to speed up again to merge onto the freeway. For the remainder of the drive (approx 25 min), everything was fine. We have not taken the car in yet for inspection. The car charge was over 50%. I had driven the car on the freeway with no issues for an hour earlier in the morning, for 15 min in the city, and then for another 25 minutes on the freeway prior to the incident.
The car does not switch from Reverse to Drive under certain conditions, resulting in uncommanded reverse motion. Gear selection on the Ioniq 5 is controlled by a twisting knob at the end of a stalk on the steering column. Drive is selected by turning upwards, Reverse by turning downwards. The moving part springs back into the neutral position once a gear is selected. Occasionally the car does not switch from Reverse to Drive. This is extremely dangerous as the vehicle shoots backwards when the driver is expecting it to move forward. A driver will likely press the accelerator more firmly after having physically moved the gear selector to Drive and expecting the vehicle to move forward. Since this happens after backing up, it is likely that obstacles or persons are behind the car when this happens, and absent a very fast reaction by the driver this will result in accidents and injuries. The issue is triggered when the car is not at a complete standstill when Drive is selected. Even barely noticeable residual backward motion triggers it. There is no haptic feedback to alert the driver that the car ignored the driver input. As drivers are expected to pay attention to their surroundings when maneuvering, visual feedback (via the gear indicator on the stalk and possibly a dashboard notification) is not useful. There is a small auditory cue, but it is easily missed when in a conversation or listening to music, especially because the car frequently dings, pings, and beeps for other reasons. Not to mention, hearing-impaired drivers will also miss this. The driver should not be able to physically move the gear selector into the Drive position when the car is not accepting that input - the twisty bit should be locked out to prevent this. Or at the very least, if a crucial driver input is discarded, the car should instead default to a safe behavior, i.e. put the car in Neutral instead of Reverse.
Driving on freeway when adaptive cruise control turns off and had a sudden complete loss of acceleration, we had steering and brakes only. Sudden reduction of car speed in traffic could cause accident. Has only happened once in 20k miles. (no acceleration) Adaptive cruise control shuts off for no reason, but dealer couldn't replicate. In recent 8k trip we photographed warning on dash 17 + times after shut down. Dealer couldn't find any saved trouble codes for this. No warnings prior to any occurrence only after, dash turned off on acceleration loss.
See uploaded photos and document.
After owning and driving the 2023 Ioniq 5 for about 4 months, the car was driven from Massachusetts to Arizona. After driving across the county at 75 mph about 50 min on cruse control the car began to lurch, the speed would drop about 3 mph below the cruse control set point, then accelerate to a mile faster than the set point and then settle down to the set point. This would happen multiple times during the next 100 miles before stopping to charge. After charging and again on cruse control at 75 mph or so, the lurching would begin again. After the lurching started, the power display indicated the front motor on this dual motor vehicle was doing all the work to drive the car, and the rear motor was no longer functioning. Later it was confirmed that the rear EOP (electric oil pump) which cools the rear motor was not functioning at all. As a result the rear motor would increase to more than 170 degrees F and stop operating. No DTC was stored for the EOP Actual Speed of zero (despite an EOP Command Speed for 800-3000 rpms). No DTC was stored for the MCU Motor Temperature overheat. No DTC was stored for the MCU Motor Actual Torque of zero when it was commanded for something more. Fortunately the Hyundai Ioniq 5 did command the front motor to take over even though the rear motor was no longer functional, so the car was able to maintain speed most of the time. However, the car is normally 325 hp with both motors. Accelerating with only the 95hp front motor on a heavy car was very slow, both in traffic and on the highway. The lack of performance could easily surprise an unsuspecting driver resulting in a collision or worse. I know of at least 5 owners who have experienced this issue. In each case Hyundai has been slow at best and refused to repair at worst. The issue is without DTC but can none the less be easily diagnosed by observing the ODB EOP Actual Speed (when the car is driven) will be zero with an EOP Command Speed >0 .
I drove on the freeway around 70 miles/H last July 14th, 2023 with my wife. But suddenly the speed dropped down after I dropped my car at NORM REEVES Hyundai dealer. They keep 4 days for the test. They said all test is OK. But I am afraid to drive on the freeway. I Leased Jun 17th, 2023 new IONIQ5. Is this OK? What should I do?
Occasionally, the vehicle sometimes doesn't start and allow me to engage to Drive gear from being turned off/Parked. I sometimes have to turn the car off and back on 1-2 times for the car to start like normal and allow me to select drive or reverse. Additionally, I have never been able to successfully sync my vehicle with my hyundai bluelink account despite efforts to troubleshoot with Bluelink representatives.
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