Most Ford vehicles (including Lincoln & Mercury) with direct TPMS systems learn TPMS sensors manually. Typical method for initializing learn mode is by tapping the brake pedal and turning the ignition on in a certain sequence; then a TPMS tool can be used to trigger the sensors for registration. Some models enter into relearn mode using the hazard-flashers switch. A TPMS relearn should be performed when rotating tires or replacing sensors.

Potential problems with manual learning: horn doesn’t beep when testing sensors or vehicle picks up a sensor emission from a nearby car.

If the horn doesn’t beep when the sensors are triggered, then technicians can roll the window down or drive the vehicle forward a few feet and then try the relearn again. Also moving to an area with less RF interference and away from other vehicles might help.

Ford vehicles have particular standard for sensor IDs – those equipped with OE banded units must start with a 1 or a 2, and snap-ins a 3 for early models or a 6 for late models. If the sensor ID starts with the wrong number, then the horn won’t beep when the part is triggered during a relearn procedure.
More information on IDs for banded sensors can be found here, and snap-in sensors here.

For other issues with manual relearns, OBD-learning and OE cloning are options.
There’s no time limit when learning via OBD, and it’s the same process as other vehicles (Honda, Toyota, etc). The IDs are written directly to the ECU so it’s not possible to learn a sensor from a nearby vehicle.
If the original sensors are cloned, then the relearn can be skipped. Cloning OE sensors can be done by either testing the OEM part (ID copy) or by manually entering the ID numbers into the tool when programming sensors. The Alligator-TPMS website also has a guide that shows how to find OE-sensor IDs.