I had this, plugged in diagnostic. it told me it was the front NS inner sensor. So i swapped it with the inner offside sensor and the diag still told me it was on NS inner. So we know the sensor is good. This left me with the wiring. I physically started to check cable and connectors from the sensor and found a broken cable where it ran behind the lower front grille.
Can't quite remember but on the drivers front wing from the engine bay i removed the headlight and under that is a multi connector with all the front sensors going to it. I used a continuity tester to test the each cable individually from this connector to the sensor.
You do need to have a diagnostic to tell you which sensor is the problem, i used the ELM327 device.