2025 HYUNDAI IONIQ 5 Complaints

I was driving my vehicle on a freeway with 3 passengers when i heard a muffled pop or thud from behind me. A rear passenger confirmed that it came from beneath the rear seat towards the left side of the car. The vehicle speed immediately dropped to less than 40 mph and a warning message appeared on the dash "Check electric vehicle system". I later noticed a red battery icon appear on the left of the dash. I pulled over after leaving the freeway and attempted to resolve the issue by turning off the car, then restarting it. The notice and red battery icon still appeared. I feel that this sudden reduction in speed is a safety issue because I could have been driving at a higher speed (65-70 vs 45-50). Following cars may not have been able to stop in time, or I cuold have been forced to attempt to get off the road by entering lanes with vehicles travelling at a much faster speed. I was about 5 miles away from home on the start of a 400 mile trip so decided to turn around. Back at home I discovered that a new DTC code had been thrown during or after this event - P1A9096. I transferred to another person's cart to complete the trip, and on return arranged for the car to be transported to a manufacturer recommended dealership to check the issue. The Dealership service department conducted diagnostic tests and determined that the issue was caused by an ICCU failure. The have placed an order for a replacement ICCU unit and fuse. Prior to this event there had been no dash light warnings or trouble codes thrown.

Car charged as scheduled overnight 3/28/26 but was dead the morning of 3/29/26 and when it was jumped gave error "Battery overheated, please stop and exit vehicle" and "check electrical system" - vehicle has been in shop for 16 days, no diagnosis except that it "probably" needs a HV battery.

I heard a loud pop and my car died and was undriveable in about 5 minutes. Told it was my iccu failure and fuse popping. Apparently this is a common issue. I was almost killed as I was kn thr interstate and needed to be towed. Nothing worked

2025 Hyundai Ioniq 5 XRT, VIN [XXX] . Four 12V battery failures requiring jump-starts in under 800 miles of ownership. No fault codes stored at any failure event. Visit 1 (01/12/26, ~100 mi, RO HYCS79193): Factory OEM battery confirmed failed by GDS. Replaced under warranty. Visit 2 (01/30/26, ~300 mi): Second OEM battery confirmed failed by GDS. Replaced. Visit 3 (03/31/26, ~800 mi): Aftermarket AGM tested healthy but required jump-starts. GDS recorded 12V SOC dropping from 99% to 21% then recovering to 79% — consistent with intermittent LDC output interruption, not parasitic drain. Hyundai Techline contacted. No repair performed. Visit 4 (04/08/26, ~800 mi): AGM measured 5.5V, required jump-start. Maryland Lemon Law notice submitted to Hyundai Motor America. The Ioniq 5 has no alternator — the 12V system depends entirely on the ICCU’s DC-DC converter. Hyundai has acknowledged this ICCU defect under NHTSA Recalls 24V-204 and 24V-868, covering 2022–2024 Ioniq 5 models. The 2025 model uses the same E-GMP platform and ICCU architecture but is excluded from both recalls. My symptoms — repeated battery failure with no DTCs, confirmed SOC anomaly on GDS, failure across two battery chemistries — match the subclinical LDC failure mode documented in those recalls. A Hyundai North America case is open and engineering has been engaged. No repair has resolved the defect. I request NHTSA investigate whether the 2025 Ioniq 5 is affected by this defect and consider expanding Recall 24V-868 to the 2025 model year. Please add this complaint to Investigation PE23-011. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The Integrated Charging Control Unit (ICCU) failed after just 7400 miles on 2-6-2026. The vehicle would not drive faster than 25 miles per hour and had to be towed to the dealership for repair, where it took approximately one month to be returned to me. There was a "Check electric vehicle system" message on the dashboard.

The 12V battery in my 2025 Hyundai Ioniq 5 failed under normal use, causing repeated loss of vehicle function. Voltage measured ~12.3V at rest, dropping to ~12.0V when opening the door, and collapsing to ~11V then ~9V under light load (headlights), resulting in system shutdown. After a failed start attempt, the vehicle experienced a brownout followed by a complete loss of 12V power for approximately 5 minutes while the battery was replaced. After installing a known-good replacement battery, the vehicle powered up and the instrument cluster displayed “The vehicle is On, Ready” without pressing the start button or providing any operator input. Due to safety concerns, I did not attempt to move the vehicle. Concern: After a complete loss of control power, the vehicle appears capable of entering or reporting a Ready state without explicit operator action. A vehicle should not present or enter a drive-ready state following a power interruption without a new, deliberate user command. This behavior is unpredictable and could present a safety risk if the system were to enable propulsion or mislead the operator about the vehicle’s state. At minimum, it indicates improper state recovery after a power failure.

On April 1, 2026, my 2025 Hyundai IONIQ 5 experienced a cascading electrical failure. The vehicle first displayed a warning about a problem with the on-board charger, followed shortly by an alarm and the 'Stop Vehicle and Check Power Supply' warning with a red 12V battery indicator, rendering the vehicle unsafe to drive. Had I been on the freeway this would have been extremely dangerous. My Bluelink diagnostics history confirms three fault codes from that date: P1A9096 (ICCU fault, Electric Vehicle / Air Flap system, still Open as of 4/3/2026), and P056216 (Voltage Regulation fault, Hybrid Control system, reported twice), consistent with a cascading ICCU failure causing 12V system collapse.

The vehicle flashed a warning not to drive the car because of an electrical system problem after a loud popping noise. I had the car towed to a dealership who told me the Integrated Charging Controller Unit had failed. The car is only 9 months old with under 5000 miles.

ICCU completely went out. Had to have the ICCU replaced with an upgraded one, fuse replaced and software was updated.

Integrated Charging Control Unit (ICCU) failure leading to a loud popping sound from the rear, total loss of drive power.