Possible ICCU issue

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R P

R P

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Well, today it happened to me with my I6. Was out this morning, and when I was ready to return home, I got the message to check electrical systems (something like that) and saw the little red 12V battery icon. I put it in drive, and it immediately went into limp mode. I was about 10 kms from home. Could only go about 38 kph. Then about 7 kms later, it went down to 19, and then 9 and stopped completely about 1 km from home. I called my wife and she came out to rescue me with our other car. I attached a jumper cable and let the other car charge the 12V for about 15 min. I then was able to drive almost home before it quit again. One more charge with the jumpers and I was able to put it into the garage. I tried charging the 12V with an external charger, but it would not charge up past about 25%.



I called a tow truck and had it towed to the dealer. They will be checking it out further but think also it is an ICCU problem. If it is, they said there is at least a 2 or 3 week wait for a new one. But they will cover a rental car. They will confirm the issue and let me know tomorrow.



But needless to say I am not happy, I have heard here about this ICCU issue but was not sure how common it was. The dealer said they have had to replace a few already. The car had just over 27K kms. Now makes me wonder if I can trust this car on a trip again. I have taken a few long trips and never an issue. And I take it skiing regularly. If this would have happened further away from home, I really would have been hooped.
 
R P said:
Well, today it happened to me with my I6. Was out this morning, and when I was ready to return home, I got the message to check electrical systems (something like that) and saw the little red 12V battery icon. I put it in drive, and it immediately went into limp mode. I was about 10 kms from home. Could only go about 38 kph. Then about 7 kms later, it went down to 19, and then 9 and stopped completely about 1 km from home. I called my wife and she came out to rescue me with our other car. I attached a jumper cable and let the other car charge the 12V for about 15 min. I then was able to drive almost home before it quit again. One more charge with the jumpers and I was able to put it into the garage. I tried charging the 12V with an external charger, but it would not charge up past about 25%.



I called a tow truck and had it towed to the dealer. They will be checking it out further but think also it is an ICCU problem. If it is, they said there is at least a 2 or 3 week wait for a new one. But they will cover a rental car. They will confirm the issue and let me know tomorrow.



But needless to say I am not happy, I have heard here about this ICCU issue but was not sure how common it was. The dealer said they have had to replace a few already. The car had just over 27K kms. Now makes me wonder if I can trust this car on a trip again. I have taken a few long trips and never an issue. And I take it skiing regularly. If this would have happened further away from home, I really would have been hooped.
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Sorry to hear about that, hopefully a replacement is readily available (keep us posted). Did you receive any warning or indication from BM2?
I was investigating and found a related ICCU TSB (Integrated Central Control Unit) as described in the TSB.
Unfortunately, the 2024 Kona EV is listed as an affected vehicle as well as I5 and I6, hope the 25 MY Kona EV I own will not be added later:rolleyes:
 
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I have had 3 recalls already with the ICCU. They were all just diagnostic checks with some software updates. The last one said they added software to put it into limp mode instead of a hard stop. I guess that is what I experienced today.

What worries me, too, is that on the other Ioniq forum have been hearing about these ICCU issues with the I5 and I6 for about 2 years. And some have had their ICCU replaced more than once. Seems like Hyundai hasn't figured out the problem yet, which is not a good sign.

Reminds of that tick tick problem on the previous gen Konas. I had that, too, but at least it was a gradual thing, not leading to a hard stop. I don't remember Hyundai ever acknowledging a design or defect issue, just kept replacing gearboxes and motors. May not want to own this car past the warranty period either. It's a shame, really like the car in all other respects.
 
R P said:
I have had 3 recalls already with the ICCU. They were all just diagnostic checks with some software updates. The last one said they added software to put it into limp mode instead of a hard stop. I guess that is what I experienced today.

What worries me, too, is that on the other Ioniq forum have been hearing about these ICCU issues with the I5 and I6 for about 2 years. And some have had their ICCU replaced more than once. Seems like Hyundai hasn't figured out the problem yet, which is not a good sign.

Reminds of that tick tick problem on the previous gen Konas. I had that, too, but at least it was a gradual thing, not leading to a hard stop. I don't remember Hyundai ever acknowledging a design or defect issue, just kept replacing gearboxes and motors. May not want to own this car past the warranty period either. It's a shame, really like the car in all other respects.
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I edited my reply- any sign from BM2 beforehand?
 
I have a BM2 on it, but have not been checking it regularly, so not sure when or how long this issue has been brewing. I removed it prior to getting the car towed in. Didn't want to give the dealer any excuse to suggest that might be the cause. I should have checked it first, as it keeps history as long as it is connected. But too late now.

I assume the dealer can check for codes, so they might know when it went bad. I used to see the orange charging light on the dash come on regularly. But thinking about it now, haven't seen it for a while.
 
R P said:
I have a BM2 on it, but have not been checking it regularly, so not sure when or how long this issue has been brewing. I removed it prior to getting the car towed in. Didn't want to give the dealer any excuse to suggest that might be the cause. I should have checked it first, as it keeps history as long as it is connected. But too late now.

I assume the dealer can check for codes, so they might know when it went bad. I used to see the orange charging light on the dash come on regularly. But thinking about it now, haven't seen it for a while.
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I just picked one up but haven't installed it yet. When I do I will keep a sharp eye on the charging cycles, but I don't think I will be changing my habit of regular utility mode initiations.
 
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Heard back from the dealer this morning, and here is the scoop. It is indeed an ICCU failure and needs to be replaced. The bad news is that there is a large backlog for this unit, and it will probably take 4+ weeks to arrive. The good news is that it is a new part number that supposedly fixes whatever was wrong with the old one. The service guy said that until recently they were replacing ICCUs with the same old part number, which may explain some repeat replacements.

Because it is under warranty, they will provide a rental car, incl reimbursement for gas (since my car is electric). And of course the tow will be covered, too. So I guess it could have been worse (stuck somewhere far away), and with the new part number hopefully it will be fixed for good.
 
R P said:
hopefully it will be fixed for good.
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Each generation of Hyundai/Kia EVs has a key part that makes potentially thousands of vehicles inoperable (or limp) when it fails. Because the company doesn't want to slow the production line, existing customers have to wait a long time for the fix. Will the EV3 and EV4 have yet another show-stopping part or will the company do enough testing to make sure their EVs are reliable?
 
insightman said:
Each generation of Hyundai/Kia EVs has a key part that makes potentially thousands of vehicles inoperable (or limp) when it fails. Because the company doesn't want to slow the production line, existing customers have to wait a long time for the fix. Will the EV3 and EV4 have yet another show-stopping part or will the company do enough testing to make sure their EVs are reliable?
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My Kona had the tick tick issue, but it did not affect driveability or was in any danger of sudden stoppage or limp mode. If you ignored it, then at some point maybe would become more serious. But it my case, it was hard to even replicate for the service guys. I had both the gearbox and motor replaced, at different times, with appointments of my own time choices. That fixed the issue (again new part numbers). Each only took one day. So no big deal, basically same as if you were taking in your car for any service appointment.

The other issue was the battery replacement, and again no worries about it suddenly blowing up or catching fire. The chances of that were so extremely remote, esp after the software update to monitor the battery. Again only one day to replace. And Hyundai took good care of us with gift card worth $1000. No complaints about that.

The ICCU issue (only other common issue that I know of) with the I5 and I6 was a little more serious in that it could leave you stranded somewhere needing a tow. Luckily for me, was able to limp home with it. But sounds like it is fixed with the new part, so I am good with that. Will be a wait, though, to get my car back.

But they gave me a nice AWD rental (Ford Escape Platinum trim) and will reimburse me for all the gas I use. It is a hybrid, so pretty cheap on gas, but since free doesn't matter. I have been driving it today, and just emphasizes for me again why I like an electric car, and in particular my I6. The Escape is a nice car, for those that have never owned a BEV. But I sure miss the instant, nimble acceleration and deceleration with the Hyundai regen. It actually has regen, too, and shows it on the dash, but still have to use the brakes, or it will coast too much. Very hard to beat the driveablity of the Hyundais.

I will say, though, that my Solterra (built by Toyota) has been completely flawless since I bought it. That is indeed a very high quality car, and also drives very well. Not to mention is great off-road, which I needed for getting to our cabin.
 
R P said:
Interesting article about 12Vs and ICCUs.
https://insideevs.com/news/752720/ev-12-volt-battery-problems/
In the 2nd last paragraph they suggest that deep cycle batteries might be better suited for BEVs.
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And another ICCU article today @ Inside EVs
Hyundai’s ICCU Problem: Here’s What We Know

Interesting recall report PDF detailing production dates and affected models. I notice Kona EV not in there, specific to E-GMP platform, but this is the first year (2025) Kona EV has V2L so I would imagine similar ICCU characteristics- who knows and if new part# ICCU is installed and is exempt?
 
Well, I'm hoping with the new part number, the issue is fixed. The service guy said this was new. Previously they were just replacing with the old part number.

Seems to only affect the 800V cars. Maybe the 800V to 12V conversion puts extra stress on the ICCU that causes them to fail.
 
Not yet, haven't called the dealer since I left it there. They initially said 4+ weeks, so will wait until then. From the main Ioniq forum, many others are in the same boat, waiting for the new improved ICCU (new part number) to arrive.

I am OK with my AWD rental, and made a lot of ski trips with it over the last few weeks. Nice knowing that my gas will be reimbursed, too, so have no qualms about using it extensively. I do miss the I6 though, and this rental just confirms why I would never buy an ICE car again, incl a hybrid like this one.
 
The new part came in today, and they are installing it now, along with a new 12V battery. Car will be ready to pick up tomorrow. I took it in on Mar 5, so about 3.5 weeks to fix, which is actually a little faster than they estimated. So with the new updated ICCU, shouldn't have to worry about future failures.

I put on about 3500 kms on the rental, and paid $439 in gas, which will be reimbursed. They also will be reimbursing me for the tow cost from my home. Pretty happy with this dealer in White Rock (where I bought the car), a lot better than our local Langley one.

And will be great to get back to driving my I6 again. I sure missed it.
 
Just got back from a 6592 km trip to the Yukon with my Ioniq 6. Didn't want another ICCU failure up there, as nearest Hyundai dealer is in Prince George, BC, a couple thousand kms away. But all went well, and car performed flawlessly. Was a great trip.
 
I really hope they have this fixed, as I am a fan of Hyundai and Kia vehicles and am seriously thinking of a Kia EV3 or EV4 when I get a new car in a year or two. But I sure don't want my car to strand me on some rural road 10 miles from nowhere.
 
Sure would be nice if they could produce a new model coming out the gate with no major issues. Problem is you don't know until a year to two later. I am OK with minor issues that are easily fixed with a recall. But battery replacements, motor/gearbox (as with this tick tick issue), and ICCU are not minor. And they never tell you what exactly the problem was and how the fix was applied. I am still nervous about the ICCU issue, because there is no advance warning, your car just quits. And after towing it to a dealer, you then need to wait 3 or 4 weeks for a replacement. So far, as far as I know, there have not been repeat failures after the fix. But I still do not have full confidence. Having said that, I am not going to stop using it for trips. After all that is the main reason I bought this model. It really is a great car to drive and in all other respects.
 
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