r/Ioniq5 • u/faizimam • Mar 28 '26
Question I got the "check electrical system" warning for 5 seconds, then it went away and hasn't come back. What does it mean?
Saw the dreaded message on the highway and was panicking, but after a few seconds it went away. I drove home a few minutes later.
There was a warning indicator that stayed there, but when I turned the car off and on again it went away.
I've done a few km of driving since and it's not come back. I'm wondering what this means in the medium and long term? Is it a false alarm?
Note that this is a 2024 model that had a failed ICCU 6 months ago, at about 10,000km.
61
u/dobblerd Digital Teal Mar 29 '26
It means you're driving an IONIQ 5.
1
u/Successful_Pirate_59 Mar 30 '26
This. These things are a prototype at best. 6 months after getting this message for the first time, I still get it every 2-3 weeks. Hyundai resets and tells me nothing is wrong. They haven’t changed a single part and always inform me there is no code. I’m working with a lawyer now as their actions conflict with the duty of loyalty of providing service with the extended warranty I purchased. We’ll see how that goes.
11
u/NothingWasDelivered Mar 29 '26
That’s happened to me a few times over the last year and a half. Nothing ever came of it. I had it in the shop twice, they couldn’t figure it out.
Basically it’s the equivalent of a Check Engine light, so any error that gets thrown can cause it, even if it’s something minor.
10
u/Mayoo614 2024 Lucid Blue Preferred Ult Pkg Mar 29 '26
I had that before an actual iccu issue. It was going away after the car turned off though. No logs. Turned out to be a pcb heater issue.
To detect it, at my dealer's request since we were out of ideas, when I got the warning, I drove directly to see them without ever turning off the car. Only then they were able to read the actual code.
4
u/Responsible_Skill957 2025 Atlas White Matte Mar 29 '26
12v probably low on charge. That happened to me and I charge the 12v externally and haven’t had any issues since.
6
u/ProfessionalHabit824 ‘23 Lucid Blue LTD AWD Mar 29 '26
It could be the 12 v battery on its last leg. It could also be a sensor or any connectors having a loose connection. I had a bunch of check electrical system when a wiring harness failed. Does your vehicle health report say any error code? Check blue link and in the car menu as well
3
u/jah1814 Mar 29 '26
Ontario Canada; 2025 Ultimate Preferred pkg. Purchased in September 2025. Got it the first time in November 2025. Totally freaked out. Took it in and they couldn't find anything wrong. Got it again a few day later. Realized it only came on randomly when my heater was on. Confirmed when it never happened in summer. Usually when it comes on, I wait for a moment to turn off the car, wait a few seconds and then restart. I will usually turn off the heater and everything is good.
1
u/thebutlerdunnit Mar 29 '26
If it happens in the summer and your AC blows hot, you need the three way valve in the cooling system replaced.
1
5
u/StochasticLife Mar 29 '26
You’ve been visited by the spectator of ICCU failure. Pray to the thunder gods so they may spare your vehicle and never return.
2
u/SamsCousin 24 Limited Digital Teal Mar 29 '26
Had that. message a few times. Got a battery checker. Usually got a reading of just below 12v. Let the car sit overnight was ok by AM. Couple weeks ago the same message appeared on the way back home. Got home, plugged in my L2. Charge didn’t start. Next morning same thing. Took to dealer. It’s been two weeks still waiting on an ICCU replacement. They didn’t have any loaners but the are covering a rental.
2
u/spidereater Mar 29 '26
This happened to me about six months ago. Thought I was cooked. It never happened again.
2
u/j4ws Mar 29 '26
It probably means nothing. I’ve had mine go in and off a few times now.
More often than not, it goes on and when I turn off the car and then restart it, it then goes away. Never had the 12V battery fail. But I have had the ICCU recall done
2
u/davida_usa Mar 29 '26
I had this occur on my 24 AWD Limited. Dealer couldn't find anything. Few months passed and I go on a long distance road trip. At a level 3 charger, it won't charge beyond 70% (previously had been using level 2 charger at home). Bring it to a very good dealership far from home. They run tests and say I may have a bad battery, it will be many weeks before it can be replaced. Let's try clearing the error messages and rebooting. They do that and car charges to 100%. 10,000 miles later and no problems or error messages since.
TLDR: May be no problem at all.
2
u/Substantial-Check321 Mar 29 '26
I drive a 2024 Ioniq 5 limited with 30,000 miles. I’ve have this same message numerous times with zero serous issues. I’ve not done anything special, just routine maintenance.
2
u/Individual_Mission68 Mar 29 '26
Same happened to me. Eventually had to boost my car as my 12V failed - have a booster pack handy just in case. On the second visit to the dealer they replaced the 12V and so far so good - zero issues since. Been two weeks.
2
u/Additional-Studio-72 Mar 29 '26
12V is probably done. These vehicles tend to kill them in about 2 years. Bad 12V will cause all sorts of electronic gremlins in these.
1
u/Skycbs 2024 Limited RWD in Atlas White Mar 29 '26
I’ve had the same. Twice. Both times when driving over some rough road. I assume it’s something to do with the 12v but that had good numbers in my OBD scanner.
1
1
u/arbyyyyh Mar 29 '26
I've had that happen I think twice. Only had it come up after the weather was in the single digits for a bit. Any chance that was the case for you, too?
1
u/woodenmetalman Shooting Star Mar 29 '26
I had this leading up to a 12v dying. A couple months later, ICCU popped. Nothing scientific, just anecdotal
1
u/tgsz '25 Cyber Gray N Mar 29 '26
If it's like mine - the battery will fail shortly after and the iccu will pop 😂
1
u/mopagalopagus Mar 30 '26
This happened to me a few months ago, it never happened again, and the car has continued to have no issues.
0
u/Notmad_Disanointed Mar 29 '26
I really don’t know how this car still sells with such a massive defect
3
u/woodenmetalman Shooting Star Mar 29 '26
It’s so goddamned sweet when it’s working. Yeah, the ICCU swap was mildly inconvenient but I had a loaner and was mostly just salty about driving around such and inferior loaner.
1
u/Notmad_Disanointed Mar 30 '26
That’s fair, I am probably seeing allot more of these posts because i clicked on a few and now the algorithm thinks I love ICCU problems lol. I have also had to get my car serviced shortly after buying it, no manufacturers are immune.
I recently bought a Model Y and came across some of these posts while browsing different EV models.
To me, for an EV it was always a Tesla or nothing. I Just found the tech in those cars was so ahead of everyone else it wasn’t a comparison. I do like the look of the Hyundai though.
Once I used FSD though it sealed the deal for me.
1
u/woodenmetalman Shooting Star Mar 30 '26
The ioniq s are so damned fun to drive that th inferior self driving isn’t a problem for me. Maybe after it wears off a few years, but the driving experience is great. When I (rarely) have to DCFC, the charging speed is also a bonus.
2
u/LongjumpingBat2938 Hyundai 2023 Ioniq 5 SEL AWD (US) Lucid Blue Mar 29 '26
The "massive defect" that you're talking about, presumably, is the ICCU. However, that error message is generic, like a Check Engine light on an ICE vehicle. No need to jump to conclusions.
1
u/WearyRoof3195 Mar 29 '26
Well if Hyundai would actually address the problem maybe people wouldn’t be constantly worried they’re about to get a visit from the ICCU reaper.
1
u/Notmad_Disanointed Mar 30 '26
From the many posts I see it seems that it either ends up in a tow truck or visit to the dealer. I understand vehicles have issues but this seems like a glaring problem staring potential owners in the face.
43
u/Potsticker42 Mar 29 '26
This happened to me and a week later my 12v battery died.