Move the vehicle into open sky and allow time for a cold fix. If the screen is mounted deep in a metal dash, the GPS antenna may be shielded, which no software setting can fix.
Metal dash structures and heat rejecting windscreen film both block GPS. A film that keeps a car cool in a Dubai summer can also stop a GPS lock, and it is the cause nobody suspects.
Check in order:
- Open sky. Test outdoors, away from buildings and covered parking.
- Time. A first fix after long storage takes longer than a warm fix.
- Screen mounting. A screen surrounded by metal has a shielded antenna.
- Windscreen film. Metallic or heat rejecting film blocks GPS signal.
- Speed source. If speed is set to GPS and there is no lock, speed reads zero. Switch the source to ECU or wheel speed as a test.
Related: RPM Works but Speed Does Not · Where to Mount Your Elite Dash Screen · Units and Values: Metric, Imperial and Display Formats
