Owner-reported complaints naming the driver-assistance system, filed with NHTSA
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Reports naming forward-collision avoidance, lane keeping, back-over prevention, cruise control and related electronic driver-assistance systems. Every record below is an owner-reported complaint about the 2026 Hyundai Ioniq 9 submitted to NHTSA — not a confirmed defect, not a recall and not a manufacturer bulletin. 8 reports on file name it.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Shown in the owner’s own words, exactly as filed
I was driving at 35 mph speed on a straight road and the car automatically activated emergency steering and pushed towards right I had to jerk the steering towards left to prevent any accidents. No adverse event occurred however this was unnerving experience.
On May 14, 2026, while traveling at highway speed in a clear passing lane with no obstacles present, the autonomous emergency braking system activated without cause and brought the vehicle to a complete stop. A following vehicle nearly rear-ended me. I recorded a voice memo immediately after the incident. A third-party crash detection application on my phone independently logged the hard stop event. A second phantom braking incident has since occurred. The vehicle is a 2026 IONIQ 9 Calligraphy leased in March 2026. This is the second major defect event on this vehicle, which was also out of service 28 consecutive days for a sunroof failure earlier this year. I am aware of ICCU-related systemic defects documented across the Hyundai and Kia EV platform and believe this may be connected.
I was driving on the highway at 70 mph approximately with my young daughter in the backseat. All of a sudden, the front display on my Hyundai Ioniq 9 went completely black and said "no signal." I lost all dashboard information about my speed, gas gauge, horsepower etc. The only thing I could do was see how fast I was going because I was on google maps and my audiovisual screen in the center was still working. I drove 15 min with this to the dealership. The signal never came back. I had the car at the Planet Hyundai for 14 days. They said nothing was wrong and that I should come back when it happens again. It was TERRIFYING having no signal and wondering if my car was going to stop in the middle of the highway. The dealer said that Hyundai would not do anything about it unless it was recreated even though I had pictures of it. What a horrible experience and I am terrified to drive the car now.
Was driving down the highway when Check: electric vehicle system warning came on and car slowed suddenly and wouldnt go past 41MPH. Within a min, the car slowed down further and just as I was pulling on the shoulder. Car didnt have power to move after.
On April 23, 2026, while driving my 2026 Hyundai Ioniq 9 , the Automatic Emergency Braking system completely failed to detect an oncoming hazard. The system did not alert me, did not activate, and did not apply emergency braking. I nearly collided with another vehicle as a direct result of this failure. The vehicle has a persistent diagnostic trouble code C28AB87 — CAN time-out for the front radar unit — which disables critical Advanced Driver Assistance Systems including Automatic Emergency Braking, collision avoidance, and Smart/Adaptive Cruise Control. This is the same defect that has been present since early in my lease. The vehicle has been presented for repair at two different Hyundai dealerships on three separate occasions: Attempt 1 — Oxmoor Hyundai, [XXX] , March 19-20, 2026. Defect diagnosed, unable to repair. Attempt 2 — Oxmoor Hyundai, [XXX] , April 1-17, 2026. Front radar unit replaced. Defect remained. Attempt 3 — [XXX] Hyundai, [XXX] , April 23, 2026 to present. Suspected bad connector, part ordered. Vehicle still at dealership. Cumulative days out of service: 24 days and continuing for the same safety defect. I have formally demanded a buyback from Hyundai Motor America under Ohio Lemon Law ORC 1345.72. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
The vehicle was plugged in overnight. To the set 80% limit. When I got up to leave for work and take family out. The vehicle check electrical system warning ⚠️ came on and the then the vehicle would not drive past 41mph. Then in a few minutes dropped down to 28mph and would not go any further. Took the car to dealership which was miles away and 18 miles per hour was my top speed when I pulled in to the dealership lot. This was one day after I had dropped the car off for a route 7K mile tire rotation and filter change. They claimed they topped off fluids. I keep reading that the ICCU is failing on the Ioniqs and this symptoms seem to match. I am now waiting on diagnosis to be done Tuesday or Wednesday this week of the 5th.
While driving on the freeway utilizing Highway Drive Assist, I suddenly received a warning on the heads up display stating that assisted systems were unavailable, at which point the Adaptive Cruise Control & Lake Keep Assist both deactivated. I pressed the button on the steering wheel to reactive the system and received "conditions not met" error. At this point, I placed my foot on the accelerator and it was completely unresponsive. I stabbed at hte accelerator as well as held it down without issue. Regenerative breaking also did not reactive. Fortunately, I had enough momentum to change lanes safely to the shoulder and power cycle the car. I took the car to my local dealership who did a brief test drive and could not recreate, returning the car to me without contacting Hyundai proper, and recommending I call them directly myself.
Occasionally while driving my IONIQ 9 in sunny conditions with glasses on while utilizing Lane Keep Assist and the Adaptive Cruise Control system the car flashes a Warning about keeping your attention on the road, and then continues on beeping and chiming before ultimately completely stopping in the middle of the road unless you disengage the Lane Keeping Assist and Adaptive Cruise Control. I believe the sensors on top of the Steering Wheel aren’t calibrated that great for people who wear glasses, as this issue does not occur when I take my glasses off. I am not in any way obstructing the sensors, and in all cases when this has occurred, my attention is on driving and the fact that the vehicle begins to decelerate into a complete stop while in the middle of traffic is terrifying. This has happened to me about 3 times now since getting the car and all 3 times it was while I was wearing my regular glasses. When I have my sunglasses on I haven’t experienced the issue.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Categories with enough reports to have a page of their own
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