so after almost three years the ICCU got me

[GreyGV60]

I wonder how many E-GMP platforms won't suffer an ICCU failure in their life??
On another forum a contributor surmised that the E-GMP platform prioritised not reducing HV range over keeping the 12v battery healthy.
Perhaps a solution:
Have smart charger from AC mains when car is parked??
Bypass the ICCU 12v side with a smart charger plugged into the V2L socket, I'm not certain if the V2L can be left switched on, and keep the battery charged from that??

Back it 2022 when I got the GV60 there are many repots about 12v battery failures in the Ioniq5. As the Ioniq5 shares the same platform I had been charging the 13v battery once a week

I wonder how many E-GMP platforms won't suffer an ICCU failure in their life??
On another forum a contributor surmised that the E-GMP platform prioritised not reducing HV range over keeping the 12v battery healthy.
Perhaps a solution:
Have smart charger from AC mains when car is parked??
Bypass the ICCU 12v side with a smart charger plugged into the V2L socket, I'm not certain if the V2L can be left switched on, and keep the battery charged from that??

since 2022 I have been hooking up a noco battery charger to the 12 volt once a week.( I hardly drive the car. In 3 years I don’t even have 6000 miles on the car). With that said my 12 volt is still healthy (per the techs at Genesis) and my ICCU still failed.

 

[gknyce]

With that said my 12 volt is still healthy (per the techs at Genesis) and my ICCU still failed.

For those who had their ICCU fail over the last ~6 weeks....
- what % do you charge at-home vs. public-chargers
- for public chargers, specify L2 or L3/DCFC
- for at-home charging... what amperage is your L2 charger set to?

 

[GreyGV60]

For those who had their ICCU fail over the last ~6 weeks....
- what % do you charge at-home vs. public-chargers
- for public chargers, specify L2 or L3/DCFC
- for at-home charging... what amperage is your L2 charger set to?

Since 2022 on average I charged on a L3 only 14 times each year, then the rest on L2 and at home with a 40amp. Since this past March I charge 100% at home.

 

[Gen-EV]

re: ICCU failures, this is being posted on Reddit right now -

https://www.reddit.com/r/Ioniq5/comments/1p9hpm1/potential_iccu_culprit_and_solution_found_by

- it's an interesting write-up by the German EE guy, over my head, but still generally understandable. His hypothesis is that it is humidity/moisture/condensation from the cabin through the breather-vent on the ICCU (or at least that is what I gathered). Zero idea how legit this is/is not, but it was an interesting read. SIdenote - I was always curious about the GV60 (E-GMP) setting to dry the cabin automatically, 30 mins after you part, having run the A/C - ostensibly to prevent mold/odors, but maybe more?

I finally got around to reading this write up. Although I want this to be the smoking gun, I see holes in the theory. First, the ICCU in all E-GMP vehicles the ICCU is mounted under the rear seat inside the conditioned cabin space. Yes, there would be humidity fluctuations in the passenger compartment, however I do not feel that they would be extreme enough to be the sole cause. In addition, the A/C and defroster would pull the humidity out of the cabin while driving and prior to charging. To put it in comparison, how often do you enter your car and find condensation or frost on the inside of your windows? Next, if this was the smoking gun the recall would be to install a desiccant breather on the ICCU, a simple and inexpensive fix. Also, all new E-GMPs would come with the desiccant breather installed.
Now here is the REALLY BIG HOLE. The E-GMP'ers have the ICCU under the rear seat. I have the G80 EV and us non-E-GMP'ers have the ICCU mounted under the hood and exposed to all of the weather extremes. I have many of the same components (including the ICCU) the vehicle just isn't the same bottom up build as the E-GMP. So, if humidity and condensation is the issue the G80 EV (and possibly the GV70 EV) should be leading in ICCU failures by percentage of sales volume. Knock on wood, I have not had the failure yet. I also AC charge at 6kw/24amps most of the time which per Ed is a factor to consider.

To see the breather port location go to 24:10 in the video I posted previously.

Side note:
How much pressure would build up if the ICCU was sealed? About 3L of air expanding and contracting with the temperature changes? Would the cover plates need to be more robust?

 

[noremacnova]

Side note:
How much pressure would build up if the ICCU was sealed? About 3L of air expanding and contracting with the temperature changes? Would the cover plates need to be more robust?

The Ideal Gas Law (PV=nRT) and more specifically Gay-Lussac's Law apply. When a system has constant volume and amount of gas, then P ∝ T, or P1/T1 = P2/T2, where T has absolute units (e.g. Kelvin).

Assume the lowest service temperature might be 0degF = -18degC = 255degK, and the highest service temp as 110degF = 43degC = 316degK.

Assume the coldest temp produces an atmospheric pressure of 14.7 psia. Then the highest temp would result in a pressure of 14.7 * (316/255) = 18.2 psia, or an increase of about 3.5 psi.

 

[gvjim]

I have the G80 EV and us non-E-GMP'ers have the ICCU mounted under the hood

Does the G80 have the exact same ICCU?

 

[Gen-EV]

Yup. Part# 36401A

Electronic Control - 2023 Hyundai Ioniq 5

HyundaiPartsDeal.com offers genuine Electronic Control for 2023 Hyundai Ioniq 5 with great price and fast delivery.

www.hyundaipartsdeal.com

 

[GreyGV60]

Yup. Part# 36401A

Electronic Control - 2023 Hyundai Ioniq 5

HyundaiPartsDeal.com offers genuine Electronic Control for 2023 Hyundai Ioniq 5 with great price and fast delivery.

www.hyundaipartsdeal.com

View attachment 63242
View attachment 63243

At the end of the day, I'm not so sure that any of us can do anything to prevent an ICCU from failing. We can worry about it, overthink it, but there are somethings that may be out of our control. If we are driving it normally and following proper maintenance, what else can we do. Enjoy our cars and hope for the best.

 

[rbreeze]

It may not be a factor, but it should be noted that the location of the ICCU in the Electrified G80 and Electrified GV70 is not under the rear seat, but rather under the hood. I usually lurk in the Electrified GV70 forum and I have yet to read about an ICCU failure occurring on an eGV70. Of course, in my saying this I've probably just jinxed myself!

 

[Hanabanana]

I can't find any reference on this site (GV60 forum or overall) about this. There should be, so, from September 2025...

Hyundai ICCU Class Action Lawsuit Filed in Canada

A Hyundai integrated charging control unit (ICCU) class action lawsuit in Canada alleges the 12-volt batteries won't charge if the control units become damaged. This can cause a vehicle to enter a reduced power mode which causes a loss of power to the wheels.

www.carcomplaints.com

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Help support this site so it can continue supporting you!

 

[GreyGV60]

I can't find any reference on this site (GV60 forum or overall) about this. There should be, so, from September 2025...

Hyundai ICCU Class Action Lawsuit Filed in Canada

A Hyundai integrated charging control unit (ICCU) class action lawsuit in Canada alleges the 12-volt batteries won't charge if the control units become damaged. This can cause a vehicle to enter a reduced power mode which causes a loss of power to the wheels.

www.carcomplaints.com

Below is from the law firm for the proposed Class Action in Canada. Since you brought up the issue, do you wish to take the lead and start a forum post on this issue? You can also contact the attorney firm to see if there is any such talk in the U.S. about a proposed class action lawsuit.

Hyundai/Kia/Genesis (ICCU Defect) Class Action​

A proposed national class action has been commenced in the Province of British Columbia concerning certain Hyundai, Kia, and Genesis vehicles. The action alleges that specific models and model years are equipped with a defective Internal Charging Control Unit (“ICCU”), which is responsible for charging the vehicle’s battery and powering low-voltage accessory equipment. It is alleged that these ICCUs are prone to inevitable failure when subjected to voltage and/or thermal stress (the “ICCU Defect”).

The ICCU Defect arises from the use of inadequate internal power transistors within the ICCU, which are alleged to fail: (i) upon voltage stress; and/or (ii) from thermal stress due to a faulty cooling system which is prone to rupture and leakage. The failure of the internal power transistors short-circuits the ICCU, resulting in a blown fuse, thereby cutting off electrical power to the vehicle’s essential components, including the 12-volt battery and the high-voltage traction battery pack, which can cause a loss of motive power so as to create a real, substantial, and imminent risk of harm, injury, and/or death to vehicle occupants.

“Affected Class Vehicles” include, but are not limited to, the following:

• Genesis G80 (2023-2024)
• Genesis GV60 (2023-2024)
• Genesis GV70 (2023-2025)
• Hyundai IONIQ 5 (2022-2024)
• Hyundai IONIQ 6 (2023-2025)
• Kia EV6 (2022-2024)

Contact Us

Please contact us should you have any questions and/or if you are an affected owner/lessee. You can reach us at 1-844-672-5666 or email us at classactions@mckenzielake.com.