NHTSA Complaint #11467554 — 2021 FORD EXPLORER

While in a driveway at a decline (approximately 5% grade), I placed the vehicle in park and set the emergency brake; when I decompressed the brake to turn the vehicle off it took off sliding down the street. A coworker was with me and was about to get out at the time as well. Fortunately I was able to gain control before I hit the mailbox in front of us and no one or thing was injured This was the second time this happened; however, the first time the emergency brake was not set. Also, starting at 23k miles, I am repeatedly getting a "Auto Hold system fault" error every few days. This occurs sometimes at startup and sometimes while driving and the Auto Hold will not work when it comes up. However, if I stop and restart the vehicle, it will go away and work. I am not sure these are related.