broken sensor (harness) wire. The wire that runs down to the sensor on the hub -- vibration/movement over time and age of car is the issue. Best to try testing the sensor with a meter at the connector that's inside the engine bay on the strut tower. Might try jiggling the wire as well while running the test to see if that makes the meter reading change?
I fixed this issue on my car by buying (for cheap ) the sensor and wiring from a parts car.....