The benign causes
Direct low sun into the lens, dense fog, heavy rain, and a windshield that is dirty or iced over on the inside all produce it legitimately. So does snow or ash packed against the glass.
It clears when conditions do. Clean the inside of the glass in the area behind the mirror — that patch collects a film that is easy to miss and sits directly in the camera's view.
The dashboard reflection cause
A light-coloured object left on the dashboard reflects into the windshield and into the camera. Paper, a phone, a receipt on a pale dash — enough to confuse it.
This one is common and instantly fixable.
The one that needs attention
If the warning appears persistently after a windshield replacement, and it does not clear with clean glass and good conditions, it means the camera is not seeing what it expects — usually because it has not been recalibrated, or because the glass in front of it has optical distortion.
That is not something to drive around with indefinitely. The system is telling you it is not confident, and automatic emergency braking is one of the things it runs.
What to do
Clean the inside of the glass behind the mirror. Clear the dash. See whether it recurs in good conditions on a well-marked road. If it persists, get the calibration checked — and if the glass was recently replaced, raise it with whoever replaced it.
Need this done rather than explained? There is no shop to drive to. We come to wherever your car already is — your driveway, your workplace car park, an apartment lot, or the side of the road it stopped on — anywhere in greater Sacramento, with no call-out fee and no mileage charge. Give us the year, make and model and you will have a firm price before the call ends.