1) You can try a soft reset and/or reseting the collision warning system. Google for instructions.
2) Dirty or blocked sensors - Located on most Lincolns on drivers side, lower grille behind fascia.
3) A weak battery will do this, but you should get "system charging" warnings.
4) Low brake fluid, or bad brake fluid level sensor.
Hopefully, it's one of those. It's not a common problem. Regards,