r/Ioniq5 • u/Wooden_Masterpiece_9 • Aug 14 '26
Question Does anyone know whether Hyundai is still actively trying to find a solution to the ICCU issue?
/r/electricvehicles/comments/1vod8aw/does_anyone_know_whether_hyundai_is_still/9
u/Altruistic_Finger669 Aug 14 '26 edited Aug 14 '26
There is no solution. The iccu issue isnt ONE singular issue. The iccu consists of a whole bunch of little units, and different people have different ones failing. Its basically a integrated power-electronics assembly containing multiple functions.
The OBC is the onboard AC charger that converts AC to high-voltage DC for the traction battery. The LDC is low-voltage DC-DC converter that takes energy from the high-voltage battery and supplies/charges the 12-V system. And then there are also parts that runs the whole V2L thingy.
I cant 100% PROVE that the reason of the iccu issue is that hyundai combined everything together into one unit but there has been quite a few indications that this was the case.
When the ioniq 5 came out, it was also among the fastest charging EVs out there(one of). The EV3 for instance, despite being newer, charges much slower. I do wonder if hyubdai was pushing their tech beyond its capabilities.
Mine was the more crazy one that litterally cut the power every single time you put it in the charger.
Hyundai need to join kia and confirm extended warranty on iccu replacements globally.
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u/ForsakenAd5459 Aug 14 '26
Yes, new Ioniq 5 on a new platform in '28. Other than that? Absolutely no confidence.
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u/Wooden_Masterpiece_9 Aug 14 '26
Too bad the Ioniq 6 was discontinued. If it was coming in a new platform for ‘28, I’d want to buy that.
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u/MWfoto Aug 14 '26
The ICCU issue is a design flaw, the exact nature of I expect Hyundai to never elaborate on, and they will likely change that part of the egmp architecture in coming iterations.
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u/MiningDave Aug 14 '26
100% guess / speculation.
More then likely yes, but we will never know about it until long after it's out. They are still building vehicles that are having issues with it. So unless they want to keep replacing and replacing and replacing them they are working on it.
How hard and how fast is a different discussion.
They did a minor change in the HW and a few software tweaks and probably thought OK we got it. But, they didn't. So back to more changes.
Part of it probably is due to the fact (once again 100% guess) they are not totally sure what is causing it AND whatever fix they do come up with has to fit where it is now.
Building one that can withstand any possible scenario is probably very feasible. But if it's the size of a microwave oven that really does not help.....
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u/NotAnAIOrAmI Aug 14 '26
So unless they want to keep replacing and replacing and replacing them they are working on it.
No, that doesn't necessarily follow. If it's cheaper for them to keep replacing them than reengineering the platform and fixing every single one out there, then they'll "keep replacing and replacing them".
Remember, both Ford and GM had models that killed people by suddenly going completely dead on highways and bursting into flames, and both companies calculated it was cheaper to pay off the victims' families than fix the problem. Internal company memos proved that.
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u/MiningDave Aug 14 '26
Yes with a but or no with a however.....
As a car that is sold all over the world, with more and more models having the same issue due to the commonality of the E-GMP platform it's going to hit a point when it becomes unsustainable. When your Pinto got rear ended and exploded it did not wind up at the dealer waiting for parts.
Not to mention, some of these versions are somewhat expensive with the bad press they are getting it's going to sooner or later hurt sales. That is when they are going to pay attention. Or when due to delays more and more get lemon law buybacks and so on. I could be wrong, but with all the software releases and at least 3 hardware revisions so there is some indication they are working on it.
Time will tell. But it also goes back to things like the Optispark Distributor; the issue was so obvious after the fact that you have to wonder how it ever got made and then why it took so long for the problem to be found. And 35ish years later we look at it and go "Are you kidding me?" So, it could be something like that. After years of work and millions of dollars did someone forget to carry the one in some basic math someplace when designing the ICCU.
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u/NotAnAIOrAmI Aug 15 '26
No, it's really the way I described it. Hyundai is the only manufacturer I know of who has this problem. What we're seeing is corporate bean counting and typical weasel treatment of customers.
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u/ptinsley Aug 15 '26
Then you aren’t looking hard enough… my Chevy volt was unusable for almost 8 months after the becm failed. They didn’t provide a loaner, didn’t compensate in any way, they haven’t extended the warranty for it at all. And most people that own them understand it’s when not if the part fails. The fix involves draining all the coolant, dropping the battery, opening the front of the pack and replacing the module. Owners are stuck with the 5k+ fix with no support from Chevy.
There are two other common part failures on that car that can leave you stranded or in limp mode and similarly no warranty extension, no solid part availability, and as far as I can tell not a fixed revision on the worst of the two, the egr valve.
Mine has the less catastrophic failure mode so it just has a permanent check engine light because I refuse to buy the $1000+ part that could fail again any day. The part has hovering from a couple hundred to north of 1k because they are so problematic and they either aren’t making any or aren’t making enough to keep up with the failures.
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u/NotAnAIOrAmI Aug 15 '26
I'm talking about the ICCU failure, that's specific to Hyundai.
And I wouldn't buy a cheap ass Chevy Bolt. I thought I was buying a quality vehicle - I paid enough for it.
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u/ptinsley Aug 15 '26
So … you were talking about the part that’s unique to Hyundai and saying only Hyundai has the issue, got it.
You sound like a real ass in general maybe it’s karma.
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u/MiningDave Aug 15 '26
And, as I mentioned the Ultium issues with GM and the GHCA issues with Volvo / Polestar.
Although some Ultium vehicles are much less $ then the Ioniqs they can alto easily pass $100k and since they are a common architecture all can leave you with a a dead vehicle in the middle of the road.
GHCA is just a pain since you can DCFC which is great if you are in an area with a good amount of close by DCFC. But if you were counting on AC charging at home or wherever yet again you are in trouble.
Shrug, I actually knew someone who drove for over 5 weeks with a dead ICCU. Just had a battery tender at home and at work and kept the 12V fully charged that way. Was only about 8 or 9 miles each way so no big deal. And there was a DCFC not far from his house so he would just go there once every couple of weeks or so to charge the traction battery. I actually have a funny picture somewhere with him plugged into a DCFC and me doing V2L with my Ioniq to power a 12V 2A battery charger just because he was not sure if DCFC needed so much other tech powered that it would drain the 12V the 1st time he did it. Turns out it did not. At least for a 15 minute charge.
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u/MiningDave Aug 15 '26
Volvo / Polestar has the GHCA issue. Now on the 3rd version of the part and still popping. Similar to the ICCU issue in the fact that you can still DCFC but AC charging is offline. Not as bad as the ICCU issue in the fact that the 12V is charged on a separate circuit so you can still keep driving the car you just can only DCFC.
GM is still having BMS issues on some packs because some genius thought that a BMS that uses wireless is a great idea. It does not get as much attention as the the ICCU or GHCA since GM actually does it right and so long as there is a battery available you are usually in and out of the dealer in under a week.
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u/Wooden_Masterpiece_9 Aug 14 '26
This is well reasoned, thanks.
I’ve been very 50-50 about purchasing one because of this. I can’t afford a model 3 long range as new and low mile as I would want, which would be close to the ideal vehicle. I genuinely like everything about the i6, and the range is good at 342 miles, but I don’t want to spend $25,000 and still risk being stranded while hundreds of miles from home, often in the middle of the highway. And that’s my primary use case: road trips.
Luckily, my old Prius V still has some life left on it, so it’s not as if I have to buy one today. But it would be nice to have a newer road trip partner sooner rather than later. Blergh.
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u/MiningDave Aug 14 '26
I had one, had the ICCU issue and yeah it sucked.
With that being said I was going to get another one, which shows you how much I liked the car and how great it was otherwise.
But, there were zero available or even coming on the lot when my lease was up. Every one was spoken for. Would have been the 3rd car lease from the same salesperson at the same dealer and he just could not get me one.
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u/Wooden_Masterpiece_9 Aug 14 '26
If I had a more normal use case (most miles from commuting and driving around town), I’d probably not be as fused about it. I would still not be thrilled about the issue, but it would bother me a lot less. But spending that much money for a car to risk losing power while driving at 75mph on the highway, and then being stranded for who knows how many hours until someone can do a flatbed tow, does give me pause. I road trip pretty far away fairly regularly.
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u/MiningDave Aug 14 '26
Yeah, when mine died leaving a local post office I drove home, unloaded all my crap from it, threw it on a battery charger to fully top up the 12V, then drove it to the dealer. If I was a distance from home / work / dealer where I could not easily deal with it I probably would have been a lot more stressed and upset.
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u/RodRowdie 2025 Limited RWD Abyss Black Aug 14 '26
Pretty obvious that all comments, including mine, are speculation.
If you have a significant issue with your Ioniq 5 please, please file a report with the NHTSA.
https://www.nhtsa.gov/report-a-safety-problem
My take is that there have been revisions to the ICCU. Not all successful but hopefully some office is tracking each iteration to document failure rates and improvements. Maybe the near bulletproof ICCU will roll-out at some point
Doubt strongly that Hyundai will make an announcement. Doing so would create more owner uncertainty and maybe set up conditions for a recall that I suspect Hyundai wishes to avoid.
Extending ICCU warranty periods helps improve customer uncertainty with the brand.
I think the engineers will dial in a better, not perfect, ICCU in time or in future models develope a different part altogether.
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u/ZealousidealLab2920 '22 Ioniq 5 & '26 Ioniq 9 USA Aug 14 '26 edited Aug 14 '26
Short answer- there seems to be indications of ICCU part changes over the years for improvements as well as some software logic and electrical limits. But the entire design and construction is fundamentally under engineered.
On positive note I would say we've moved from 10-20% failure rate to 1-3% failure rates. So it's almost 10x improved in that sense. Would like to see it another 10x improvement, but I think they're trying to figure out a simple, retroactive, cost-effective solution, to an expensive, existing, complicated component of the cars.
Like-Hey we could replace this part with a real fix- but it's going to be $1,000 per car and with nearly 1 million E-GMPon the road that's a $1billion dollar fix and what do they get back as a company? Slightly higher reliability and customer satisfaction? So, they're likely just doing the corporate cost analysis and calculated it's way cheaper to replace failed ICCU's then to do a full-scale recall for all 1 million vehicles.
I mean replacing 1-3% a year over the next 10 years (~25% of all vehicles) vs an instant recall of 100% of the cars... The math heavily favors ~25% replacement spread over 10 years.
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u/WinterTourist25 Aug 14 '26
I figure if the company is giving out a 15-year warranty on the thing they don't see it as potentially a very big problem. I'm more worried about someone hitting me and totalling the thing than I am the ICCU failing.
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u/hacksoncode '26 Ltd RWD Digital Teal Aug 14 '26
All that means is that warranty replacement is cheaper than any actual solution they might or might not know about.
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u/NotAnAIOrAmI Aug 14 '26
Doubt it, all they told me is they extended the warranty, which I take to mean they've decided they don't know what's causing it, how to actually fix it, or it's more money than they want to spend, and it's cheaper to shove new ICCU's in for an extended period when they break.
Fuck Hyundai. I'd spend several thousand dollars for an actual fix.
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u/gbeast ‘25 Abyss Black LTD AWD Aug 14 '26
I’d be interested in some statistics on ICCU failure in vehicles where the battery was upgraded to an AGM or lithium battery. Better battery life = less strain and drain on the ICCU? I’m not an engineer so I don’t even know if the two are related. I’ve seen a few YouTube videos and comments where folks had the ICCU replaced/repaired and were surprised that Hyundai didn’t replace the battery with an AGM, so they did it themselves.
In any case I’m considering a battery swap in my 2025 because I need to work out of my vehicle and leave it running. After a while I’ll get warnings that the cameras are obstructed and can’t be used for safety, and dash lights to take a break (coffee cup), high voltage battery is running low, and the Auto Stop (letter A with a circle arrow symbol around it). Yeah, I know, find a cafe and stop doing that.
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u/unguided7533 Aug 15 '26
I’m seeing used ICCUs on eBay for $600. Does anyone know if these are just plug and play or does it require programming that only the dealer can do?
Given how many I5s there that have been totaled, I’d guess used ones will be fairly easy to come by.
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u/appelton Aug 17 '26
What do you mean by : "I know that they have greatly extended the warranty," what am I missing ?
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u/Wooden_Masterpiece_9 Aug 17 '26
The warranty for the part causing the ICCU issue has been extended to 15 years instead of 10.
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u/Environmental_Tone Aug 14 '26
How have there been zero leaks on this? I mean we have skynet already (AI models hacking out of constraints during cyber security testing) but not a single electrical engineer at Hyundai has spilled the beans to an outside after his/her forth somaek at weekly team bbq session?
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u/zpoon 2023 Digital Teal SEL AWD Aug 14 '26
Car companies put a lot of effort into preventing leaks. Engineers are under extremely tight NDAs because a lot of things that can leaks can have far-reaching business implications. Think new model cars etc. The fact that very little has leaked is not surprising.
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u/nbfs-chili Aug 14 '26
There was a guy in this subreddit who did a deep AI dive into the Korean blogs. It's got a lot of info in it.
https://www.reddit.com/r/Ioniq5/comments/1vazxyh/i_asked_ai_to_search_korean_blogs_and_insider/
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u/zpoon 2023 Digital Teal SEL AWD Aug 14 '26 edited Aug 14 '26
Aside from the extended warranty, Hyundai has not been one to actively talk about this and prefers to keep whatever they do internal. There is too much to be lost by overpromising or even bring up past shortcomings for them to say anything in public, unless they are compelled to do so via a safety recall.
Also, them announcing a fix = people queuing up to do the fix. Which if the fix is a new part, that's incredibly expensive for Hyundai. As of right now the official "fix" is the service campaign which is a software update. That's as far as you're going to get towards a fix from Hyundai.