NHTSA Complaint #11541153 — 2023 KIA SORENTO PHEV

We were driving on the highway at about 65 MPH. Without warning, the vehicle suddenly started to struggle and slowed to about 40 MPH. We were able to safely pull over, but we were in an acceleration lane merging onto another highway and didn't feel safe due to the sudden deceleration. This is a plug-in hybrid. We have driven at 65+ MPH on long rides before, and this was the first time that we noticed that the battery had completely drained. We expect that when the battery is drained that the car would function like a normal hybrid and continue to function in a safe manner. The car's cluster displayed a message along the lines of "Maintaining hybrid mode," although it isn't clear if the speed-limiting behavior was an expected consequence of that. After being pulled over for a bit, the battery level recuperated enough that we attempted to resume driving on side roads. Battery level varied from red to blue (normal) and then back to red, but thankfully the battery didn't fully deplete again and we were able to return home safely. We're waiting on an appointment with a dealership to have the car checked out. It was last serviced 3 days prior to the incident (first oil change, filters changed, etc).