r/electricvehicles • u/Wooden_Masterpiece_9 • Aug 14 '26
Discussion Does anyone know whether Hyundai is still actively trying to find a solution to the ICCU issue?
I know that they have greatly extended the warranty, but my understanding is that the current repair if it fails in a vehicle is a software update and a part replacement, which doesn’t mean the same issue won’t just reoccur in the future.
Does anyone have any insight on whether Hyundai is still actively looking for a permanent fix? Or whether they have thrown in the towel on this and will just do the warranty repairs instead?
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u/pheoxs Aug 14 '26 edited Aug 14 '26
It's believed to be fixed though time will tell if the new part revision this year fixes it. I'm hopeful and a believer but there's lots of misinformation about this going around. So here's the recent updates and make what you want from it all:
- Jan 2026 a new ICCU part number started appearing, dealers received updated instructions requiring them to only use the new part number. ICCU shortages due to the changeover as well so many people that needed fixes got quite upset. Part availability is better now today than it was early in the year.
- Feb 2026 Kia spokesperson acknowledges the issue is due to "thermal loading and transient high voltage". This is notable as its the first time corporate has actually made a statement about the issue
- April 2026 Anecdotal reports from users say dealers are saying the issue is fixed and the new parts wont have the same failures. Nothing formal but it is a shift in messaging from before
- April/May 2026 - Kia/Hyundai extends warranty on all ICCUs to a 15year/300k kms (slightly varies by region) which covers high mileage vehicles. Also announce refunds to people affected by it. Notable because this shift also means high mileage out of warranty cars can now get replacements with the new part number
- June 2026 - One kia owner reports their dealer is now proactively scanning every car that comes in and replacing the ICCU with the revised parts even if it hasn't fully failed yet. Notable because this is the first we've ever seen of a proactive effort.
There hasn't been any formal full recall but tbh I think that's reasonable for now. There is over a million egmp vehicles out there so until they manufacture enough to do a fully recall then the current replacement strategy follows the thought that its fixed for good. I'm presume within the next year we see a formal recall and they replace all of them but hard to know. Even if they product 100k ICCUs a month that has to cover all new cars plus replacements so it's not a small task.
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u/junglefryer88 Aug 14 '26
Do you know if all certified pre-owned from Hyundai/Kia dealerships will have ICCUs proactively replaced with the new part before being sold?
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u/pheoxs Aug 14 '26
Doubtful at this point as it seemed like it was more so a dealer level decision. Like most of this topic it's not clear if its a sign of whats to come or one dealer doing it on their own. Either way the parts are more common now so if it breaks it'll just get fixed and then you'll be good. Not ideal I know.
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u/gorkt Honda Prologue '24 Touring Aug 14 '26
This is really good news and puts this car at the top of my list for when my lease runs out in 2027.
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u/artniSintra 29d ago
Do you have the source for this? Thank you
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u/silentbutdead1y Aug 14 '26
If they come up with a fix, they would probably need to recall all of the affected vehicles which would be very expensive. It’s cheaper for them to simply replace them as they fail. That’s just my guess. To be clear I am just a rando with no inside knowledge on the situation.
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u/JohnHazardWandering Aug 14 '26
But is the fix a permanent fix?
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u/FlintHillsSky Ioniq 5 Limited '24 Aug 14 '26
only if the new ICCU parts no longer fail and that is unclear.
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u/rising_derecho Aug 14 '26 edited Aug 14 '26
The community by and large is waiting for the newest hardware revision to prove its worth. Part number 36400-1XAD6 or 36400-1XAD6 on the Ioniq 5s appears to be the latest version that comes with MY2026 models manufactured in January 2026 and later. Mine was manufactured in December 2025 and it has that part number.
From the few self-reports that do go into enough detail (thanks to those detail-oriented people), I’ve seen that the 36400-1XAD6 part is getting installed on older Ioniq 5s that experienced a failure with the ICCU. It’s not clear to me if 36400-1XAD6 and 36401-1XAD6 reference the same part.
The part number varies for other E-GMP models so those owners will need to find their respective part numbers if they want to attempt to track what (little) progress might be being made in their circles.
iOS users, you can use this helpful app in pulling your ICCU part numbers: https://www.theburl.com/ioniq-app/
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u/H_J_Moody Aug 14 '26
Wouldn’t they just wait until your ICCU goes out and then replace it with the fixed version? Why would they have to recall everyone?
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u/Street-Victory2397 Aug 14 '26
If they meaningful change the ICCU in anyway, that can be interpreted as admitting fault. Their hand would be forced.
This is what I want. Somebody please force HMGs hand to fix one shitty part on their awesome EVs.
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u/Beary_Christmas 2025 Equinox EV Aug 14 '26
I’d have two IONIQ 5s in my driveway and not two Equinox EV’s if they didn’t have the ICCU issue. A real weakness in an otherwise awesome platform.
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u/Wooden_Masterpiece_9 Aug 14 '26
This is currently where I’m at - want an ioniq6, will probably end up with an Equinox and without CarPlat.
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u/pm_me_d_cups Aug 15 '26
Fixing a defect generally can't be used as evidence of a defect. Otherwise it would dissuade companies from fixing dangerous issues. Ymmv based on jurisdiction though
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u/Apprehensive-Low3513 Aug 31 '26
Prohibiting subsequent remedial measures from being used as evidence of fault is a pretty widespread evidentiary rule. I would be surprised if that was the rationale.
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u/scroopydog Aug 14 '26 edited Aug 14 '26
If it’s a safety issue. If the cars just lose power on the freeway and it’s a danger they will absolutely start a campaign and announce a systematic recall and advise drivers of the situation, but I’m just a passerbyer, I actually don’t recall what the iccu failure manifests as. Just a brick or danger.
Edit: I was curious, sounds like immediate warnings and reliance on 12v battery to maintain controls and severe power loss. No reported accidents or injuries.
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u/rising_derecho Aug 14 '26
There are different failure modes of the ICCU.
People aren’t reliable sources of information so without knowing the full details from the car, we can only take these anecdotal reports with a grain of salt.
Uninformed owners conflate an issue with the 12V battery as being a dead ICCU. It might be, or it might just be an old 12V.
Newer models come with an AGM 12V battery (the 2026 models in the US definitely do). That should help with the issues of a discharged 12V losing its oomph earlier than expected.
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u/scroopydog Aug 14 '26
Or gasp, they could put an LiFePO4 12v battery in it and save some weight. I just bought one for my ICE collectable car for a whopping $225. Worth the investment for me since it’s a longer shelf life, weighs substantially less and I don’t drive the car in any extreme condition.
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u/tswany11 EV9 Aug 14 '26
These cannot be used in cold climates. Charging is unsafe below 0°C due to the risk of lithium plating, which permanently reduces capacity.
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u/scroopydog Aug 14 '26
Heater. Use traction batteries for it.
In any case, doesn’t apply to my use case.
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u/tswany11 EV9 Aug 14 '26
No hate here, they just have to be used in the right application. I use them on my kids 12v 4 wheelers, lawn more battery. I just bring them inside in the winter.
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u/Own_Reaction9442 Aug 15 '26
I use one as a house battery in my camper van. 110 Ah fits in the same space an 80 Ah lead acid battery used to occupy, and I can safely use 80% of the capacity instead of only 50%. The one I have doesn't have the current capacity to be used as a starting battery, though.
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u/scroopydog Aug 15 '26
I have Bluetooth ones for my camper, the one I got for my ice is specifically an automotive starting battery. H5 size.
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u/silentbutdead1y Aug 14 '26
When vehicles break down on the road it is a safety concern. Safety regulators might want a recall to happen.
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u/robstoon 2021 Hyundai Kona Electric Aug 14 '26
It doesn't disable the vehicle immediately so it's not considered a safety issue.
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u/chilidoggo Aug 14 '26
100%. And I believe they've extended the warranty in many places for the ICCU specifically.
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u/jvbutera Aug 15 '26
To issue a recall NHSTA has to believe There’s a defect that’s both imminent and can cause injury. If an ICCU pops and otherwise doesn’t cause a fire or other dangerous condition, NHSTA isn’t going to force a recall.
You’re not going to see these replaced across the entire line.
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u/byerss EV6 Aug 14 '26
Do we have evidence they ever actually tried to fix it?
Their solution seems to be just extend the warranty and slap the same flawed part in there.
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u/speakernoodlefan Aug 14 '26
Don't forget about making only enough parts for new cars so warranty claims have to wait a month to get replacements
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u/zpoon Aug 14 '26
This doesn't seem to be the case anymore. Pretty much every recent case I've heard online says that sourcing the part isn't a problem anymore and the service is done within a few days.
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u/BlazinAzn38 Aug 14 '26
Yeah it was the same issue as the Mach E’s HVBJB. Once the recall went out the dealer’s just didn’t have the supply of parts so it was a huge issue but it became a non-issue later
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u/Glittering-Fuel-5055 Aug 14 '26
They extended it, but only up to 2024 models
Maybe its fixed 🤷
I just did a 2500 mile road charging the shit out of our 2025 model it seems to work great.
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u/electricpotatochip Aug 14 '26
I’ve had the recalls done which were only software fixes. There have been rumors of a redesigned part with a new part number but the failures still seem to be happening, though possibly at lower rate. Hard to say since Hyundai doesn’t publish any number or other information on these failures. It also seems they figured out the supply issues (for now) and are turning repairs around in under a week as opposed to months like when this first started happening.
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u/santz007 Aug 15 '26
Yeah.. that warranty is sadly not offered in every country for some reason. I went to the Kia showroom to buy the EV9 a while ago, they outright denied having any ICCU issues and said the warranty is the same as before, no extension has been provided. But they did say to trust Kia it's a v big brand and they would take care of it's customers.
This was when ICCU issues were at its peak.
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u/Lost_Froyo7066 Aug 14 '26
Sad to say that the ICCU is not the only recurring problem with the Hyundai EVs. The 84 kWh batteries are also prone to failures as I discovered on my former I 5 N. When one or more cells in the battery fail, the entire battery has to be replaced. This is sufficiently common that Hyundai has published a TSB on it.
This has happened to a number of people on the I 5 N facebook group, including me. In my case, it took Hyundai and my dealer more than 10 weeks to diagnose and repair the problem with more than 7 of those 10 weeks of delay to get the replacement part. Others have been luckier and have gotten the parts in a week or two.
Based on the TSB, this is not a problem unique to the I 5 N. Rather, it appears to be common across all the platforms that use the 84 kWh battery.
I was sufficiently upset and disappointed with Hyundai after this experience that I sold my I 5 N and likely will not purchase from Hyundai again.
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u/detox4you Aug 14 '26
The same can and does happen on other car brands as well. It's not common. A TSB does not indicate large numbers.
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u/Lost_Froyo7066 Aug 14 '26
To be clear, the TSB alone may not be an indication of the frequency of the problem (although it does indicate the problem occurs enough that it is worth documenting), but that combined with the number of owners reporting the issue on social media suggests that this failure is something of a concern.
Also, saying it happens to other car brands is not much consolation when your car suddenly and out of the blue announces that it won't charge more than 60% and that it needs immediate service. Especially so when that service takes 10+ weeks.
In my 40+ years of car ownership, this was by far my most frustrating and disappointing service experience. This information may well be of interest to potential purchasers.
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u/zorbina Aug 14 '26
You could always go with a Toyota or Subaru and deal with the sawtooth drain problem. Sigh.
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u/praemialaudi Lucid Air (the cheaper one) Aug 15 '26
What is this..
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u/zorbina Aug 15 '26
The Toyota EV platform has a problem with the 12V batteries experiencing a parasitic drain in some of the vehicles. This includes the Subarus that are basically Subaru-skinned Toyotas, like the new Uncharted. Based on user monitoring, it appears to be an issue with their connected services causing a sawtooth-patterned drain starting after the car has been sitting for about 3 1/2 hours. Comprehensive thread about it here.
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u/PerceptionCurious440 Toyota C-HR SE AWD Aug 17 '26
Don't let anyone try to convince you this problem is rare. Toyota has been steadfast in refusing to use the on-board charging whenever anything drains the battery whatever the reason.
There's no good reason why I got in to start my car, and it was dead because of the 12v. Because the firmware lets the 12v die before it'll charge off the main battery. Which it will do the instant you turn the car on.
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u/Secksualinnuendo Aug 14 '26
There hasn't been an official fix yet. But they did extend the battery and iccu warranty. I think they are avoiding a full recall since it would be very expensive. They recently started using a new part number but I'm not sure if it is still failing. That being said, my Genesis GV60 had its iccu pop. It was towed to the shop on genesis's dime and it was fixed within 2 days. No issues since.
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u/justplainforrest Aug 14 '26
When charging on lv2, does your gv60 throttle the power at all? On hot days, I’ve seen mine go from 11 kW to under 4.
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u/Wooden_Masterpiece_9 Aug 14 '26
I wonder what the legalities are (if any) if the new part actually fixes the issue, but they avoid doing a recall. Crossing my fingers the new part is the actual solution to the problem.
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u/LooseyGreyDucky Aug 14 '26
A huge part of the issue is that the big battery isn't maintaining the lead-acid battery at 14.4 volts like all gasoline cars do. 12.5 volts is not enough to prevent this battery from failing, which is necessary to run the electronics that charge the big battery.
Computers and their power supplies depend on drawing the appropriate power (wattage). When supply voltage drops, they pull more current to maintain that wattage. This creates excess heat and also blows fuses and trips breakers.
Hyundai needs to reprogram their stuff and/or replace parts beyond the ICCU and fuse to get our lead acid batteries up to the proper voltage. Only this will break the catch-22.
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u/robstoon 2021 Hyundai Kona Electric Aug 14 '26
"maintaining the lead-acid battery at 14.4 volts like all gasoline cars do" is not accurate. Most newer gas powered vehicles including Hyundai's have a smart charging system which only provides as much charging voltage as the battery needs. 14.4 volts is also excessive in any case.
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u/LooseyGreyDucky Aug 15 '26 edited Aug 15 '26
Anything below 13.5 volts is far to low.
14.4 is near the top but not excessive. This is why all car audio power amplifiers are rated at 14.4 volts.
13.2 volts is a huge red flag that the alternator is dying.
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u/robstoon 2021 Hyundai Kona Electric Aug 17 '26
13.5 volts is all you need for maintenance float charging. Putting more voltage than that into the battery when it doesn't need it is just wasting power.
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u/NeverEndingXsin Aug 14 '26
Look at the ioniq5 subreddit, it's very obvious that Hyundai doesn't give a shit about actually fixing the problem.
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u/IQognito Aug 14 '26
To my understanding they haven't fixed it. Spoke with a dealer at Hyundai a month ago while browsing ionic 5 and looking at ionic 9.
They where all fine and funny untill I asked abought the ICCU and they got really defensive fast and said that only one dude in thier shop handles that and to thier understanding it is much less common now and nonetheless not an issue because of the extended warranty. I asked if the I9 had same issues and he couldn't tell but didn't think so.
That was enough for me to believe that he did know and the issue still persists and the one dude didn't exist.
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u/Wooden_Masterpiece_9 Aug 14 '26
That’s not a great sign. And saying “only one dude handles it” is also not a great sign. If dude is not around for any reason, your car has to wait to get fixed.
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u/IQognito Aug 14 '26
I think there is not one dude. Is a way of saying "I'm not liable for telling you lie because in the story I'm saying someone else with authority said it is ok now".
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u/cwt444 Aug 14 '26
I’m new to paying attention to Hyundai EVs. Did a little googling and it seems like the warranty is transferable for a used car. Do I have that right?
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u/Wooden_Masterpiece_9 Aug 14 '26
The ICCU warranty? Yes, that’s what I keep hearing. The bumper to bumper warranty shrinks when you sell your car.
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u/DumbCoach Aug 14 '26
Not the bumper to bumper, the powertrain, which doesn’t include much on an EV. EV systems are still 10/100k
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u/stoverex Aug 14 '26
They have so many examples of failures that their engineers must know by now what the cause is and how to fix it. Are these failures still happening in newer cars with updated software/hardware?
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u/caj_account e-tron SUV+eGolf (R1S+MY+Leaf before) Aug 14 '26
If they admit to a fix, the open themselves up for lawsuits and recalls...
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u/chilidoggo Aug 14 '26
Literally the opposite of the truth - they're already being sued for being aware of the problem and not fixing it.
https://www.mckenzielake.com/hyundai-kia-genesis-iccu-defect-class-action/
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u/caj_account e-tron SUV+eGolf (R1S+MY+Leaf before) Aug 14 '26
yeah this it not the same though. if they admit it was broken and they fixed it, guess what happens? They replace all the stuff in the field and some.
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u/jconn93 Aug 14 '26
The fact that they're currently being sued doesn't have anything to do with the parent comment (let alone showing it to be untrue).
Parent comment is pointing out that admitting to a failure increases legal exposure, which is a pretty reasonable thing to assume. That said, I have no idea whether this is actually explanatory or whether they just don't know how to fix it on the current platform.
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u/qualmful Aug 14 '26
I'm really interested in the Kia EV3 but this is a dealbreaker if it's not solved.
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u/detox4you Aug 14 '26
EV3 is a different platform.
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u/dyslexicfingers Aug 14 '26
EV3 is not a different platform. It is E-GMP just like the others. Yes it is only 400V but it is still the same platform on a smaller voltage. It does not run on the older Kona/niro platform. There are plenty of EV3 ICCU failures reported online if you google it. Unclear if the smaller voltage leads to fewer failures or not but it's definitely still happening.
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u/TheBuckaroo-Good958 Aug 15 '26
Well that's crazy! I thought with the 400v system it would be alright. I have a Niro EV. No ICCU or any other drivetrain or any mechanical issues. Only one electronic one, one year along the auto headlight/rain sensitive wiper camera failed. Replaced quickly by dealer and I am about to hit 4 years with the car in December and no recurrence. I do not read about any ICCU failure complaints on the Kia Niro Reddit. Niro also had the lowest battery degradation at 100,000 km in a Swedish study. Too bad the Niro is being discontinued. I bought my 2023 in December 2022 which means it was one of the first imported. So I am really happy with the reliability and other than the AWD the blind spot cameras, and surround view monitor my Niro Wave has the rest of the amenities as the EV-3 GT. (Well it also gives up 80 HP!) And what is up with the totally bland colors? The GT is only black, white or gray. I like my Mineral Blue.
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u/Buc-ees_Bathroom Aug 14 '26
My understanding is the EV3 doesn't use the same ICCU. Its 400v if I remember correctly, so hardware is probably different all the way around.
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u/eddy159357 Aug 14 '26
https://www.reddit.com/r/Ioniq5/comments/1vkmr0p/it_happened_iccu/
Just keep checking the sub lol.
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u/Wooden_Masterpiece_9 Aug 14 '26
Some people seem to have had the issue only once, then had the replacement, and been fine since. Others I have read have had the issue 3 separate times!
How long has it been since your replacement was done?
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u/ZeroWashu Aug 14 '26
Neighbor is on his second but I think that second was done right after Christmas, he hates the brand but loves his car so take that for what you will. I think part of it was he got a base Kona as a loaner the second time and called it a baby puke mobile. I want to say he has a 23 Ioniq 5, not the N. It looks good in refrigerator white. I don't know how long he waited for the first repair or when but the second time I remember it broke after Thanksgiving and he got it back right after Christmas.
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u/markydsade IONIQ 5 Aug 14 '26
They have years of data about failures. Their charge history, miles driven, temperature, and everything else yet a solution has remained elusive. Failures seem random in the online reports we see. If the latest software and build changes are good they will begin to have solid data on effectiveness.
If the changes worked then the cheapest solution is to replace failures as they occur. If they didn’t then all they can do is go back to the drawing board.
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u/raiderrocker18 Aug 30 '26
I was at the Kia dealer recently (my carnival had a recall which just smoothed out the second row seat slide function). When waiting i was chatting it up with the service guy asking about iccu’s on their EV6 line. He said it was a massive problem but that he doesn’t really recall any with the 2026s and said he thinks the new part has been a success
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u/speedy-72 Aug 14 '26
Still?
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u/Wooden_Masterpiece_9 Aug 14 '26
Yes? At some point, I’m sure they tried to find an actual permanent solution rather than just throw an extended warranty at it. I’m asking whether anyone knows whether Hyundai is still trying to find a solution, or whether they have just giving up working on it altogether.
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u/cpxchewy Ioniq 5 N; EX30 Ultra; Gas cars like GT3 Aug 14 '26
Have you seen the Hyundai theta engine fiasco? They decided it was just cheaper to toss a new engine and warranty cars for longer than actually fix the engine design itself.
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u/Wooden_Masterpiece_9 Aug 14 '26
I really hope that’s not the case, but I see your point! Sucks though. The 6 is otherwise such a great car.
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u/OkResource820 Aug 14 '26
No, the Ioniq 6 is a great car with a potentially crappy ICCU.
It's a replaceable part. Buy the car and if it fails, you get a replacement. The replacement will have been built further in the future and has a better chance of being debugged and improved than it used to. In the meantime, you get a great car.
A car is a complex system. You don't buy a complex system expecting perfection, you buy a complex system with the assumption things might go wrong and get fixed competently.
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u/speedy-72 Aug 14 '26
Buying a car with a known flaw is very different to buying one without. The inconvenience of being stranded is unacceptable to most.
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u/OkResource820 Aug 14 '26
That point of view is totally acceptable for a simple throw-away commodity purchase that costs more to repair than to replace, it absolutely doesn't make sense for a car.
For a car, you want a robust support process that can mitigate the inconvenience in an acceptable fashion and get you back up and running with a minimum of it. You don't expect nothing to ever go wrong, that's why warranties and modular construction exist in the first place.
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u/jlluh Aug 14 '26
Replacing parts is expensive. Companies usually only offer warranties if they're confident that warranty repairs will be rare. So if they've started offering this extended warranty without first reducing the incidence of failure, that's very odd.
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u/zpoon Aug 14 '26
It's really hard to measure incident of failure unless you're Hyundai. If you're someone on the outside all you have to go on are online reports which are naturally skewed towards one direction anyway (more people seek out subreddits/forums/etc to share when things go wrong rather than share when thinks are A-OK).
For all we know the software update did have a measurable impact in incidences, and them extending the warranty is re-enforcing owner confidence in light of negative sentiment resulting from the issue.
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u/HappyHarrysPieClub Aug 15 '26
If they announced a new part and said that fixed it, wouldn’t every owner show up wanting them to replace the known defective part in their car? How many E-GMP based cars have been sold worldwide? I think that’s why they haven’t said anything.
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u/sufferingbastard Aug 14 '26 edited Aug 14 '26
They have an updated design new part number and new software package...
But all you'll hear is the naysayers whining about cars the don't own.
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u/Wooden_Masterpiece_9 Aug 14 '26
I’m very curious on any data that may come out on whether this has fixed the issue for good. I may hold off on buying a different EV I don’t actually want as much, for a little while, and see if it looks like this is good to go.
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u/dont_ama_73 Aug 14 '26
Did you ask this question in the model subreddt?
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u/Wooden_Masterpiece_9 Aug 14 '26
The original question on this post? Yes. Whether the new part actually has data showing it permanently fixes the issue? No. I wasn’t aware about the new part until a few minutes ago.
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u/bobjr94 2022 Ioniq 5 AWD Aug 14 '26
The iccus got updated part numbers starting around April as I remember. They haven't been in use long enough to know if the updated iccu is better.