I was driving on the highway today with my M3. When I tried to engage EAP, I noticed the car slowed down drastically. The screen showed the speed at around 45 MPH, and the speed limit showed the same. Traffic around me is going at 75 MPH. Looking at the map, it showed the M3 cursor on local street about 0.5 miles off the highway, going in the direction that's perpendicular to the highway I was on.
I exited the highway the first chance I got, googled the issue, and tried to reboot the system by doing the hard reset (i.e. pressing both thumb wheels at the same time until the screen goes blank). It didn't fix the issue. I tried again, and the problem is still there.
After I got home, I called Tesla technical support and waited 40 minutes in the queue. The technician ran diagnostic remotely and everything showed up clean. He was as befuddled as I was. He suggest for me to arrange for a service appointment to get the issue checked out more thoroughly at my local service center. He also suggested for me to disable WiFi. It sounded like the navigation could somehow lock onto WiFi and got a wrong fix on the location. It sounded fishy, but I said I'll give it a try. I disabled WiFi after I got off the phone with technical support, and, not surprisingly, that didn't fix the issue. I left the WiFi off anyone, hoping for a miracle.
I've read posts of people who went through the same. A few had the issue magically disappeared overnight. Others required their GPS antenna replaced.
Does anyone here have similar experience with your GPS unit going bad on you without warning? Did you get it fixed? How and what went wrong?