2025 Hyundai Ioniq 5

3/31/2025: New Vehicle leased. 11/24/2025: 12V battery failure. Battery replaced by dealership. 4/22/2026: 12v battery failure. Battery replaced by dealership. 6/7/2026: ICCU failure. Car cannot charge 12v battery. Car in “limp” mode - cannot drive faster than 40 mph while on highway. Fortunately was able get car to safe location to be towed. All three instances appear to be due to the same engineering flaw in the vehicle.

The driver attention warning feature is defective and often requires you to take your eyes off the road and stare at the DAW sensor in order to eliminate the car's constant "attention" warnings. Even while looking straight ahead while driving, the DAW is often erroneous and will disengage safety features (e.g., lane keeping assist, adaptive cruise control, etc.) because the DAW erroneously thinks that the driver is not paying attention. As another example, if you are driving uphill/downhill or on a curved road and are looking at the road ahead of you at a slight angle, the DAW will erroneously report that the driver isn't paying attention. The system will then disable the cruise control and lane keeping assist, creating a hazardous situation. Alternatively, the driver can look DOWN (not looking at the road) at the DAW sensor and stare at it until the car reacts. This takes your eyes off of the road and creates hazardous situations. As someone who wears prescription glasses, the problem is even worse. I cannot set a comfortable seat/steering wheel configuration where the DAW can "see" through my prescription glasses. If I want to drive in my normal position, I either need to take my glasses off or turn off the safety features (e.g. lane keeping assist and adaptive cruise control) in order to drive. Hyundai is well aware of this problem and it exists across much of the Hyundai and Kia platforms. Dealerships say that the car is working as intended. In reality, the defective DAW system creates more risk and contributes to a significantly less safe ride (as I'm constantly taking my eyes off the road to stare at the darn sensor).

ICCU failed with a pop sound in the evening. Next morning, on my way to the dealership, car started fine, alerted me about the “check electric vehicle system”, but drove fine for about a mile. Then the car came to a crawl mode, refusing to go over 20mph and stopped completely with out any indication. Luckily, I was in a quiet neighborhood and was able to steer the car to the curb safely.

When I started the car at 10pm , a loud pop was heard and warning lights on the dashboard indicated an electrical problem. I turned off the radio and anything extra that could use up power; during the next 45 minutes I took surface streets instead of the freeway to drive 22 miles back home and speed was limited to 40 mph. The next day the same warning lights were on the dashboard and speed was limited to 20mph; car lost power after 1 block. Car was towed to the dealer, where an ICCU failure and blown fuse in the engine was diagnosed by dealership and replaced.

While attempting to operate my 2025 Hyundai Ioniq 5, the vehicle abruptly displayed a 'Check Electric Vehicle System' warning accompanied by a critical red master service light on the dashboard. A diagnostic scan via the factory Bluelink app revealed a hard fault code: DTC P1A9096 (ICCU / DC-DC Converter malfunction). This failure occurred under 7,000 miles, following a previous total 12-volt battery system failure a month prior. Driving the vehicle with this specific code puts the driver at immediate risk of 'Turtle Mode' or a sudden, total loss of motive power while in motion. Living in a mountainous region where the primary thoroughfare (Highway 17) lacks shoulders, an unexpected power failure presents an extreme, unreasonable highway safety risk to myself and surrounding traffic. The vehicle had to be flatbed-towed to a dealership for an entirely new ICCU assembly

Car has only 3307 miles and incurred a DTC P1A9096. This meant the vehicle only had power from the 12 volt battery, not traction battery. Luckily, the event happened 3 miles from home and we were able to just make it. Next day upon calling for flatbed tow service, the car generated an additional DTC P05616. 12 volt battery was exhausted and nothing functioned on the car. Had to then call for a different tow truck with dollies. The failure of the ICCU (Integrated Charging Control Unit) was a cause for recall on earlier year's models. This is a major safety issue as failure of the ICCU leaves you stranded with an inoperable vehicle where you cannot even lock the doors. Currently, the vehicle is at the dealer (Lithia Hyundai of Anchorage) for repair.

While using Highway Driving Assist/Lane Following Assist on Interstate highways, lane markings frequently disappear on overpasses and in construction areas. When this occurs, lane-centering assistance silently disengages. The only indication is a small dashboard icon changing color. There is no audible warning, steering wheel vibration, or other prominent alert. The vehicle may begin drifting before the driver realizes steering assistance has been lost. Observed repeatedly on Massachusetts highways, including I-495 and I-290. This creates an unexpected and serious safety issue, potentially resulting in an accident. I had this happen during a recent trip, and multiple times the car wandered towards an adjacent lane. It caused me to lose confidence in the system, and to maintain constant vigilance, gripping the wheel tightly at all times. Had I not done so, I’m sure I would have had an incident. Who watches the dashboard all the time? The driver's eyes are supposed to be on the road ahead, especially when approaching an overpass. Had they incorporated an audible or tactile alert, this would have greatly increased the driver’s awareness and potentially avoid a crash. Since the system obviously knows when it has disengaged, it would be a simple matter to implement this. My preference would be steering wheel vibration.

I pulled my car out of the garage and proceeded to drive up the street. I suddenly heard a weird sound and an emergency warning appeared on my dashboard stating to check vehicle electrical system. I immediately stopped the car and returned it to the garage. Upon turning the car on a second time to check the message a second message appeared saying “stop vehicle and check power supply”. I called Hyundai for a tow truck to have the vehicle towed to the dealer. When I turned on the car to back it out of the garage it got halfway out and the entire system shut down making everything inoperable including flashing emergency lights, windows etc. there was very little time between the warning light going on and the car becoming inoperable. The dealer diagnosed a failure of the ICCU system which has been reported for several years. A quick Google search reveals that many Ionic owners have experienced this failure. I was incredibly lucky that this occurred within a block of my house. The previous night I was driving home on the LA freeways. Had this failure occurred at night on the freeway it could have been life threatening as there is very little time to get to safety and the hazard lights and all electronics become useless. The dealer said that they will be replacing the ICCU system with a better one. If that is the case then why wasn’t this car recalled and the ICCU replaced?