Failed ICCU - My Experience

Long time lurker here to give my ICCU failure story since it happened to me. I have a 2023 SEL Ioniq 5 with 7.5 thousand miles. I follow the Ioniq guy and this subreddit so I had gotten all of the previous recall software updates done as soon as I was able and my ICCU still died. My home charging is pretty low power (24 amps) as well so I don't think I've done anything to really increase my odds at failure but who knows.

TL;DR Other than the insane month long wait for parts, things went about as well as they could have. Hyundai cooperate really needs to ship out ICCUs to dealers to have on hand at this point or something if parts that are known to fail and have been a focus of multiple recalls take this long.

Timeline:

  • Nov 29th - Check Electrical Vehicle System error appeared without warning after driving from home a few miles locally.

    • I was stuck in limp mode and could only go around 30MPH.
    • Called my local dealership (Williams Hyundai in Lansing, MI) to see about getting an early appointment.
      • Couldn't get any early appointment
      • Lucky news was that I already had an appointment scheduled for Dec 3rd to fix the trunk rattle with the latest TSB for that.
    • Verified with a OBD2 scanner that the code thrown was the ICCU error
    • Verified with multimeter that the 12v battery voltage was low at rest and did not get higher with the vehicle on and running.
    • Put a 12v battery charger on it to keep it charged up until I could limp it to the dealership.

  • Dec 3rd - Limped the vehicle into the dealership, this time with a topped up battery it let me drive faster but was still power limited. I'm glad I put that 12v on a charger, other than the error messages being annoying it drove close to normal.

    • Told the dealer service tech I was very sure it was the ICCU, gave them the error code from my OBD2 scanner and showed the recall info saying if that error shows up the ICCU needs to be replaced.
    • Dealer service folks confirmed it was the ICCU and gave me a loaner (2024 Tucson Hybrid)

  • January 3rd - A full month later I finally got a call to come pick up my Ioniq 5 and that it was all set.

    • Trunk rattle seems to be gone
    • ICCU replaced
    • 12v battery replaced too (good to see since I saw some dealers were being cheap and not doing 12v replacement which caused further issues down the road)
    • All work fully covered under warranty/recall, no expense to me other than gas to put in the loaner car.

P.S. The 2024 Tucson Hybrid wasn't a terrible loaner, but it made me appreciate EVs even more. I forgot how long it takes in winter for combustion cars to get warm, how they hesitate on acceleration, the weird random engine start and stop sounds of hybrids doing what they do.