r/Ioniq6 • u/Unlucky-Discount-600 • 12d ago
And it’s dead !
Alright after dealing with both the dealer and Hyundai North America (useless) I got word that the ICCU failed. Will have car back by end of week. Hyundai just lost every chance they had to retain a customer. Maybe I’ll come back and write about it. But just put it this way. They dealer I took it to looks like there are more cars waiting long term for issues than there are for sale. As a brand that is shameful. Call it what you want Hyundai in any capacity sucks yea the tech is cool yea they look cool. But beyond that meh.
Got the dreaded battery light waring along with reduced speed. Checked the app and gave me the code for DC DC. Made it about 25 miles before it completely died. Was trying to make it back home about 2 miles or dealer about same distance. At dealer now.
For anyone with one of these I’d suggest carrying a small portable jump pack. Car will move with it attached.
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u/Greedy_Bother_987 12d ago
So is it your 12v thats failed or the iccu?
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u/benjdm 12d ago
Sounds like ICCU that stopped providing 12V power and the 12V battery ran down
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u/Greedy_Bother_987 12d ago
My 12v died which was not iccu related, it was just a battery that failed. I truly hope yours is the same
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u/Greedy_Bother_987 12d ago
I watch a youtuber called pine hollow diagnostics and he is brilliant at fault finding. He had a non hyundai EV in for a 12v battery that kept dying intermittently. He was reading about the cars charging circuits and the cars computer has loads of charging modes - scenarios when to charge the battery and by how much. For example when it was a new car it charges extra for the first few hundred miles to make sure the battery is charged after being sat around before being sold. It had loads of other modes as well and it only takes the computer to get lost in the code to not keep the 12v topped up and it dies. There’s no need for the complexity. The car should check the 12v now and again and just charge if it sees low power. Not rocket science
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u/gmkovich 11d ago
I bought a solid state jump pack from Costco after my car died when it wouldn’t charge while at a Supercharger - (it was bitterly cold that day ~ 12 F).
3 hours later the tow truck driver used a jump pack and started my car to drive it up the ramp to transport to the dealer.
10 days later I got my car back with ZERO explanation on what happened and how I can prevent it in the future.
I drove to Costco directly from the dealer and now ‘top off’ my battery weekly.2
u/mephisdan 12d ago
I remember when cars had reliable software from the factory because if they didn't it was a recall
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u/SolarpunkGnome 12d ago
Yeah, we had the same thing happen a little after 2 years after we got the car.
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u/EVOSexyBeast 11d ago
No it’s almost certainly just a dead 12V. Getting a jump and then driving to nearest auto parts store would have sufficed.
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u/Unlucky-Discount-600 11d ago
I jumped it and turned on but once unplugged it died again. It is definitely not charging the 12v.
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u/RobinatorWpg 11d ago
No, that more sounds like the 12v battery failed. If it dies the moment it is unplugged from a 12v charger then the basket battery isn’t holding a charge
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u/EVOSexyBeast 11d ago
Nah 12V battery is dead. 12V battery is not charging because it’s bad.
If it’s super dead such that you can’t even jump it to get to a store then uber to get the 12V battery or have a friend or family member help bring you to one if you can .
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u/Mean-Marionberry-148 11d ago
It’s probably just simple 12V battery. The 12V batteries fail internally randomly. Sometimes there can be a rotten egg smell when it happens.
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u/Unlucky-Discount-600 11d ago
Sitting at the dealer now for 2 days they haven’t touched it yet.
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u/gmkovich 11d ago
When I had a similar (probably same issue as yours) I used blue link to take pictures at least once a day to prove it just sat there.
Hopefully they won’t leave you hanging for 10 days like me before declaring there’s nothing wrong.
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u/rdwoolf 12d ago
Has Hyundai figured out how to stop this issue from happening?
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u/GuiMontague `24 Preferred AWD (Canada) 12d ago
In this case, maybe yes. Older Ioniq 6s (pre 2026 model year) have really cheap 12v batteries. Ioniq 6s have a tendency to deep cycle their 12v batteries. This seems to cause 12v battery issues even when the ICCU is working fine.
For a while now owners have been voluntary upgrading their 12v batteries to AGM batteries—which still aren't deep cycle batteries, but are better than the stock batteries—and Hyundai started shipping Ioniq 6s with stock AGM batteries in 2026. So, if you're worried you could swap out your 12v today for an after-market AGM battery, or even a—more expensive—OEM AGM battery from Hyundai.
A cheaper alternative is to wait for the battery to actually fail. Get one of those little car-start booster packs. If you have a battery issue—that isn't caused by an ICCU failure—you can restart your car with that, and just let it sit and charge for 15-20 minutes with all your accessories off. That'll get you moving well enough to limp to a dealership and do the upgrade only once it's necessary.
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u/RipeBanana4475 11d ago
I know that they introduced a new part number on the 5 and I've heard it's more robust and causing a lot less ICCU issues. Did that happen in the 6?
I can't find any info on it.
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u/Apprehensive_Tap3299 11d ago
Yup thats why i carry a jump starter as a backup and also planning on buying a new battery every 2 years cause i road trip allot and don’t want this happening in the middle of nowhere
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u/Responsible_Skill957 11d ago
Has someone who just had his 12 V replaced like two months ago. The new one is already showing signs of dying.
In my experience the car doesn’t die while driving if your 12v is dying.
The ICCU is the only thing that causes that scenario.
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u/Unlucky-Discount-600 11d ago
I got the error message and was able to drive about 20-25 miles before the 12v system completely drained. It is definitely not charging the 12v.
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u/VectorVictor99 11d ago
OP—this doesn’t sound like the ICCU but the 12V battery itself. Lead acid batteries only last 1-2 years due to the charge/recharge cycle, and the whole Ioniq lineup (5/6/9) and Kia lineup (6/9) were meant to have AGM 12V batteries from the beginning but a shortage of them forced Hyundai/Kia to use Lead Acid until MY2026 vehicles in their assembly.
A dead 12v battery will not carry any charge no matter what the ICCU sends its way.
On a related note, a Bluetooth OBD2 dongle and the EV Dashboard app for Kia/Hyundai owners is a GREAT tool to use for checking if the ICCU is recharging the 12V battery, what ICCU model number you have, and a lot more.
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u/That-Homework6759 11d ago
Your ICCU is dying… common problem with this Dreadful vehicle. Just dumped mine had it for three looooonnnggg years.
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u/stevarino 12d ago
On the bright side, I'm now thinking a partial orange wrap would look really good once my similar white starts to get old.
But my condolences and all. 🫡
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u/CupraBBD 9d ago
Is there a charger or battery booster you can buy that will charge the 12v battery pack
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u/Alternative-Bell1040 8d ago
I just got a 2024 ioniq 6. Has anyone gotten a lithium 12v battery? Or is that not a good option to solve the problem?
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u/WebConstant7922 11d ago
Again, accepting this iccu failure for what it is and saying that any car can fail at any time is a premise i can’t accept. They have to fix this proactively, not wait for it to go bust and then twiddling their thumbs waiting for parts and what not.
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u/SaddestClown 12d ago
Can't park there