Driving on freeway when adaptive cruise control turns off and had a sudden complete loss of acceleration, we had steering and brakes only. Sudden reduction of car speed in traffic could cause accident. Has only happened once in 20k miles. (no acceleration) Adaptive cruise control shuts off for no reason, but dealer couldn't replicate. In recent 8k trip we photographed warning on dash 17 + times after shut down. Dealer couldn't find any saved trouble codes for this. No warnings prior to any occurrence only after, dash turned off on acceleration loss.

- Issaquah, WA, USA

See uploaded photos and document.

- Franklin, NC, USA

After owning and driving the 2023 Ioniq 5 for about 4 months, the car was driven from Massachusetts to Arizona. After driving across the county at 75 mph about 50 min on cruse control the car began to lurch, the speed would drop about 3 mph below the cruse control set point, then accelerate to a mile faster than the set point and then settle down to the set point. This would happen multiple times during the next 100 miles before stopping to charge. After charging and again on cruse control at 75 mph or so, the lurching would begin again. After the lurching started, the power display indicated the front motor on this dual motor vehicle was doing all the work to drive the car, and the rear motor was no longer functioning. Later it was confirmed that the rear EOP (electric oil pump) which cools the rear motor was not functioning at all. As a result the rear motor would increase to more than 170 degrees F and stop operating. No DTC was stored for the EOP Actual Speed of zero (despite an EOP Command Speed for 800-3000 rpms). No DTC was stored for the MCU Motor Temperature overheat. No DTC was stored for the MCU Motor Actual Torque of zero when it was commanded for something more. Fortunately the Hyundai Ioniq 5 did command the front motor to take over even though the rear motor was no longer functional, so the car was able to maintain speed most of the time. However, the car is normally 325 hp with both motors. Accelerating with only the 95hp front motor on a heavy car was very slow, both in traffic and on the highway. The lack of performance could easily surprise an unsuspecting driver resulting in a collision or worse. I know of at least 5 owners who have experienced this issue. In each case Hyundai has been slow at best and refused to repair at worst. The issue is without DTC but can none the less be easily diagnosed by observing the ODB EOP Actual Speed (when the car is driven) will be zero with an EOP Command Speed >0.

- Blandford, MA, USA

I drove on the freeway around 70 miles/H last July 14th, 2023 with my wife. But suddenly the speed dropped down after I dropped my car at NORM REEVES Hyundai dealer. They keep 4 days for the test. They said all test is OK. But I am afraid to drive on the freeway. I Leased Jun 17th, 2023 new IONIQ5. Is this OK" What should I do"

- Gardena, CA, USA

Occasionally, the vehicle sometimes doesn't start and allow me to engage to Drive gear from being turned off/Parked. I sometimes have to turn the car off and back on 1-2 times for the car to start like normal and allow me to select drive or reverse. Additionally, I have never been able to successfully sync my vehicle with my hyundai bluelink account despite efforts to troubleshoot with Bluelink representatives.

- Chapel Hill, NC, USA

EV goes into power limited mode when on interstate when going ~50 miles while driving 70mph or more. Happened each of my 3 times on interstate of about that distance. First time was Sat 4/29 while in eco mode with 70% battery and 82?F outside, 1 hr drive 50+ miles. Second time was in normal mode Friday 5/12, 55% battery 72?F outside 1 hr drive 50+ miles. Third time was in normal mode and it happened after 42 miles. I scheduled a service after the first incident but they were only able to take it on 5/31. When this happens you lose ability to accelerate and have to coast to the side of road and let it sit for 10+ minutes to clear and then can resume, I would take surface roads after it occurred. Impacts safety for self and others, as it drastically slows without brake lights causing a high chance of being rear ended. The last incident was close to it. As it was getting worse I stopped driving on interstate with it. Car has been at the dealership's service department since 5/31. They were able to easily reproduce once they finally got to it. They diagnosed a bit and then consulted design engineers. Diagnosed on and off for a couple weeks and have finally decided to replace the drive motor. Part received Friday 6/16, to be installed tomorrow 6/20. We'll see if that addresses.

- Marietta, GA, USA

When using the most aggressive braking energy recovery mode in the Hyundai Ioniq 5 (i-Pedal), the brake lights do not illuminate despite the aggressive nature of the braking provided by this mode. This mode brings the car to a full and complete stop and is very similar to commanded braking via the brake pedal. When using the L1-L3 braking energy recovery modes, the deceleration experienced by the car is more or less mild enough that it would be similar to a downshift in a manual transmission car. But the brake lights only illuminate if your foot is fully off the accelerator pedal. I am not aware of the regulations or SAE guidance to know if this is consistent with best practice, but it could be better with the brake light coming on once a certain deceleration (x m/s2) is reached. It is my opinion that a software change in the car's ECU could effect a fix for this. A mandatory recall would force the issue with Hyundai to actually do something about it. Note that Kia and Genesis share the same basic EV platform and may share the same logic fault in brake light activation. Here is a Youtube video that discusses the issue in a fair level of detail - https://www.youtube.com/watch?v=U0YW7x9U5TQ

- Houston, TX, USA