Home » Why Everyone’s Favorite Electric Car Keeps Stranding Owners

Why Everyone’s Favorite Electric Car Keeps Stranding Owners

Ioniq 5 Hyundai Broken

The Hyundai Ioniq 5 is a lovable, retro-futuristic hatchback-ish EV, and the very first car built on Hyundai’s E-GMP platform. It’s got pixelated tail lights, bold sharp lines on its sides, fun active grille shutters, and a column-mounted shifter. Everyone who reviews it loves it, including me. But as cool as it is, we’re now learning from the car’s early owners that some Ioniq 5s have had a serious flaw, and it’s got folks from the U.S. and Korea ranting about being stranded by a brand new EV. Here’s what we know.

The Problem Is A Part Called The ICCU

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Image: Hyundai

Across the internet Ioniq 5 owners are complaining of a total loss of power that’s leaving them stranded. What’s the cause? Well, it’s a component called the Integrated Charging Control Unit (ICCU), which is tasked with charging both the high voltage battery that drives the electric motor and the 12-volt battery that powers the car’s cabin accessories (among other components). Here’s Hyundai’s description of the ICCU:

Vidframe Min Top
Vidframe Min Bottom

The integrated charging system newly developed by Hyundai Motor Group charges both high voltage batteries and spare batteries in a vehicle.

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Image: Hyundai

As Hyundai notes, the ICCU also allows discharge of the high voltage battery to components other than the 12-volt battery (which it charges through its DC-DC converter, which I assume is integrated into the ICCU). At the German Car of the Year event I attended a little while ago, Hyundai was powering a coffee maker with its Ioniq 5, as an example. From Hyundai:

Unlike previous BEVs, which only accept one-way charging, the E-GMP’s charging system is more flexible. The E-GMP’s newly developed Integrated Charging Control Unit (ICCU) represents an upgrade from existing On-Board Chargers (OBC), which typically only allow electricity to flow in a single direction from an external power source. The ICCU enables a new vehicle-to-load (V2L) function, which can additionally discharge energy from the vehicle battery without additional components. This enables BEV based on the E-GMP to operate other electric machinery (110 / 220V) anywhere. The system can even be used to charge another EV.

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Image: Hyundai

You can see the ICCU in Hyundai’s graphic here:

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Image: Hyundai

Here it is in exploded view:

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Screenshot: Hyundai

And here’s an entire (short) video on the component:

I actually saw the part in-person at the German Car of the Year event a few years ago near Frankfurt. It’s the little box sitting atop the battery pack just ahead of the rear drive unit:

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It’s on the left here:


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Reports Of Coolant Leak Problems In Korea.

So what’s the problem? Well, the electrical components within the ICCU are liquid-cooled, and a number of sources say that a manufacturing flaw — perhaps having to do with welding — has allowed coolant to leak into the device’s electrical bits. Once that happens, the ICCU’s ability to charge the car’s 12V battery is gone, leading to dead screens, windows, climate control, shifter, etc. The car just stops working — it’s bricked.

Last year, news agency United Press International’s Korean reporters Kim Hye-ran & Kim Tae-gyu wrote the article “Hyundai acknowledges coolant leak in Ioniq 5.” Here are the opening paragraphs:

Hyundai is under fire from customer complaints that the Ioniq 5 leaks coolant within the first months of usage.

Acknowledging the issue, a Hyundai Motor spokesman said Friday the leakages can be attributed to problems in production, including poor circulation of the coolant due to failure of the water pump, but that chances of a fire occurring are slim.

Kia EV6 forums, Hyundai Ioniq forums, and reddit all include threads that mention a coolant leak as a primary cause of ICCU failures. In fact, some of these threads even point out an apparent recall being instituted in Korea, with a link to a Korean forum about this issue. The forum includes a screenshot of the apparent recall, which I’ve translated below via Google translate:

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The document talks about inspecting for “insufficient optimization of welding…conditions may cause coolant leakage in weak welding areas.” The repair apparently includes some kind of reinforcement plate or simply replacing the ICCU entirely. And though Hyundai’s U.S. arm hasn’t issued such a recall stateside, one forum thread pointed out Kia’s recent U.S. safety recall notice to Niro EV owners for what seems like a similar issue. Kia states in its recall notice:

This bulletin provides information to inspect and, if necessary, replace the Electric Power Control Unit (EPCU) assembly on certain 2020MY Niro EV (DE EV) vehicles produced from June 18, 2020, through September 4, 2020. The EPCU assembly in the subject vehicles may have been produced with improper sealing. Due to this improper sealing, coolant can internally leak in the EPCU and contact the EPCU circuit board. If coolant contacts the EPCU circuit board, the vehicle may stall while driving. A vehicle stall increases the risk of a crash.



The Issues In The U.S. Are Apparently Not Coolant-Related

We reached out to Hyundai Motor America inquiring for more information, and the company mentioned that the primary issues associated with the ICCU are actually not coolant related. Here’s Hyundai’s response to our inquiry about these ICCU issues:

COMPLAINT:  12V Battery Drain.

This has been caused by 2 different unrelated issues:

  • Overactive unauthorized Bluelink use by 3rd party Apps that is waking up the car too often.
    • Resolved since 1/31 the Bluelink server is limiting traffic to 20 transactions per day. Customers informed to change Bluelink PW.
    • Most vehicles are solved since 1/31, but some came back and required 12V battery replacement failing to take charge after was dead too many times or too long before 1/31.
  • EV Light On with DTC P1A9096 ICCU related.
    • ICCU and ICCU fuse has to be replaced to resolve.
    • Some vehicles also incurred DTC P1B77 as a result of the ICCU (integrated charge control unit) failure if only ICCU fuse was replaced without replacing ICCU together.
      • DTC P1B77 cases required the PRA (power relay assy) in the EV battery to have to be replaced.

NOTE:  There is a rumor going around on forums lately about ICCU campaign in Korea for coolant leak possible related issue causing the above….

FACT:  Not related the Korea issue pertained to an Inverter Coolant Low Warning light on, not an EV Light On issue.  It only applied to vehicles before 4/23/21 Production.  Above issues have not been specific to such mfg period.

So it sounds like the coolant issue was nipped in the bud early (about two years ago), and that the real issue has to do with third-party apps waking the car up, draining the battery. Inside EVs explains this issue a bit in its article titled “Hyundai Finds Causes For Ioniq 5’s 12V Battery Drain, Reveals Fixes,” writing:

The main one is “overactive unauthorized Bluelink use by 3rd party apps that is waking up the car too often.” Basically, unauthorized third-party Bluelink apps are requesting information too frequently from the Ioniq 5. Each time that happens it wakes up the vehicle, causing significant draw until it goes to sleep.

While the drive battery has enough energy to recharge the 12-volt battery multiple times, the battery saving mode cannot keep up with hundreds of even thousands requests per day – The Ioniq Guy [on YouTube] says the PR rep told him some of the vehicles were seeing as many as 5,000 Bluelink requests per day.

Apparently there’s also a fuse that needs to be replaced to fix whatever is causing all these problems, though on some vehicles a relay has to also be swapped out.

More Than Just One Or Two Owners Have Been Stranded

I say “all these problems,” because this is hardly just one or two people complaining about their new Ioniq 5s. There are complaints all over the internet about owners being stranded. The U.S. government’s auto safety organization, the National Highway Traffic Safety Administration, includes quite a few complaints from owners, with the most recent having an “incident date” of just last week. Here are 16 of them; many of the complaints mention a loud “pop” — presumably from the fuse in the ICCU — followed by a warning light, and then the vehicle going into limp mode before ultimately dying altogether:

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Forums are littered with complaints about apparent ICCU failure causing vehicles to die on the roadway. Here are a few from the Hyundai Ioniq 5 USA Facebook page:


There are lots of these posts on Reddit, too, with user arvarkcal posting a subthread under the “Ioniq5” forum titled, “Stranded on I-80 on the way up to Tahoe, another case of broken iccu.” The thread includes a photo of the car looking rather sad, dead and surrounded by deep snow:

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Image: advarkcal

Within minutes of posting, dozens of Ioniq owners shared their failed ICCU experiences. 

Ioniq 5 Reddit 1

There are plenty of other posts on that “Ioniq5” Reddit page about ICCU issues. Here’s one titled “Disaster Struck“:

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And here’s one with a title so long, I’m gonna put it into block quotes:


After seeing so many posts about the ICCU issues, and the amount of time people have spent waiting for their cars and the back and forth with the dealers, I’m experiencing some serious buyers remorse. I’m I just overthinking it? 2023 SEL picked up 2 weeks ago.

That post basically involves someone who had recently purchased an Ioniq 5 worrying after having seen so many ICCU complaints, and learning that people have had to wait quite a while to get their cars repaired (one redditor says in his post titled “Ioniq 5 Lemon? 8 weeks I the shop – 12v Battery and Traction Battery Issues” that he’s had to wait over 85 days to have his car fixed). “Now I can’t help but feel like I’ve made a terrible mistake after reading the amount of horror stories that seem to be popping up almost daily,” the poster, pissedoffcalifornian, wrote. Redditer jasonfsmitty responded to that post by describing his own struggles, writing:

I know what you mean. My SE has been at the dealership waiting on an ICCU for 2 months, and I honestly don’t know what to do …. should I wait it out, or try to get Hyundai to buy it back? (I’ve filed a case with Hyundai, but may take another 2-3 weeks for processing). I absolutely love the car, and there’s nothing else out there I’d want in it’s place, but I simply don’t know how much to trust the car moving forward

Heres another thread from 19 days ago, this one titled “I just got this alert and now my car is dead on the side of the road. Anyone ever see this before? Please tell me it was an easy fix…” The poster includes a screenshot of the message everyone else seems to be getting on their gauge cluster when their ICCU fails.

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Here are a few responses in that thread:

  • “Ugh another! this is unbelievable.” -goldenist
  • “Sign of death. Mine happened 2 wks ago. 1 yr and 1 wk after delivery. My dealership tried to act like I didn’t know what I was talking about and that they didn’t see it on my dash. My car is now a big block of metal “waiting” – waiting for the time to run down so I can request a buyback.” -Lighter02
  • “So many of these… And the dealer just called me to tell me my reserved Limited is available. I think I’m going to cancel. I need a reliable car, not a ticking time bomb. Hyundai needs to get ahead of this and issue a recall to restore some confidence in the car. Look at how Chevy was able to turn the Bolt around…” -tenaku
  • “13 months and 6k miles and the ICCU bricked me last month, no indicators but rather randomly. I charge mostly at home. From how easily and quickly Hyundai initiated the buyback, it’s certainly something they’re very aware of. Buyback immediately triggers am NDA which is likely why we don’t see more owners posting. Just call Hyundai customer service and they start a buyback claim within minutes on affected cars.” -Remarkable_Mine_9022
  • “I got my Ioniq5 on April 14.2022 and it sopped in the middle of the road on Feb.23.2023 with just over 10k miles. It happened on right after 10 months. 2022 IONIQ5 SEL RWD. Still in the dealership. The dealership gave me the loaner right away.” -Middle-Employment61

A few things to note: First, we’ve seen a few similar-looking complaints by alleged Kia EV6 and Genesis GV60 owners, but seemingly not as many. Second, Hyundai is repairing the vehicles free of charge, so that’s great. And third, some of the above complaints could be duplicates (for example, someone who posted a complaint on a forum might also have done so on NHTSA’s website). In fact, Reddit user nedlinin posted a thread titled “ICCU, 12V, or other battery issue? This is your thread,” which includes this spreadsheet of owners who have had apparent ICCU failures:


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The spreadsheet includes 26 complaints. Compare that to the approximately 30,000 Ioniq 5s sold so far in the U.S. per data from Inside EVs, and it’s worth mentioning Reddit user screwycurves’s response to the aforementioned person who posted about buyer’s remorse:

Beware what you read here. Negative posts get most of the attention. I’ve owned my AWD SEL for 13 months and driven 25k. I don’t remember a car that’s brought me so much joy.

Obviously, there are folks who have experienced ICCU failures and haven’t responded in that spreadsheet, but it is always worth putting these types of failures into perspective. The failure rate may not be as high as the outrage on the internet makes it seem, though these are some pretty significant failure modes. Leaving dozens of brand new EV owners stranded on the road is not a good look for Hyundai’s new golden-child, its much beloved Ioniq 5 retro-futuristic hatchback.

Additional reporting by Rob Spiteri



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John S
John S
9 months ago

Weird how large swaths of this article are presented almost word for word in this video.


Mr. Fusion
Mr. Fusion
1 year ago

In regard to EVs, I still think it’s a bit funny that these absolutely bleeding-edge vehicles powered by lithium-ion batteries, still rely on the old bog-standard lead-acid 12V battery to function.

I’m not saying it’s bad design because I’m not qualified to make that judgement, but it is unexpected. Kind of like the time-traveling DeLorean still being reliant on the ICE to get up to speed. (And I should know!)

1 year ago
Reply to  Mr. Fusion

It may be an EV but lots of standard, mundane and critical automotive parts from parts suppliers around the world run on 12v DC – why reinvent the wheel with every little thing like power window motors, door lock actuators, internal and external bulbs, blower fans, switches, solenoids, relays, etc?

Pappa P
Pappa P
1 year ago
Reply to  Edward

All of those loads can easily be driven by the main battery pack.
I believe the main reason for still having the 12v platform is so that those items can still be used in case the battery pack is run empty or suffers a failure.
You can still do things like unlock the car, turn on lighting, release the parking brake, etc.

1 year ago
Reply to  Pappa P

I think the bigger part of that is safety. You don’t want the main traction battery connected and powering stuff all the time, and you need some way to power the contactor and controls.

1 year ago

I don’t buy the third-party apps claim. I believe Alec from the Technology Connections YT channel had the 12V problem and was not using any third-party apps. So either, they’re full of it, or they’re allowing unauthorized third-party apps to connect to your car. Neither is a good look for Hyundai.

Matt Dieter
Matt Dieter
1 year ago
Reply to  Ben

I don’t think he had this issue. By his own admission he had left the hatch open all night. Far more likely is that that either causes a light to stay on, or some subroutine to not shut off, especially as he has a limited trim which would have a powered hatch.

1 year ago
Reply to  Matt Dieter

Any modern car should (and typically do) have an automatic shutoff for lights/electronics after a certain time period. The car shouldn’t be able to run itself down without the user actively doing so.

Jason Smith
Jason Smith
1 year ago
Reply to  BobWellington

I’m not familiar with Hyundais, but I can tell you that the cargo area light on a 2020 RAV4 doesn’t automatically shut off when it’s been accidentally manually switched on… That was a fun welcome home surprise in the airport parking lot.

1 year ago
Reply to  Matt Dieter

Ah, I must have missed that. Thanks for the clarification!

Vetatur Fumare
Vetatur Fumare
1 year ago

I hope Hyundai fixes it and has to sell me a heavily discounted 2024 after they have developed a bad reputation.

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