Front parking sensors uses an engine bay wiring harness with the additional wiring for the front sensors. This type of harness is usually not installed on vehicles without front parking sensors. If the front sensor wiring is missing you either have to replace the complete engine bay wiring harness or make the missing wiring yourself.
Front parking sensor also requires the 6 front parking sensors and the lower grille to accomodate 2 of the front sensors.
The parking sensors are connected to the PAM module (Parking Assistance Module). The PAM module is a CANbus module that monitors the parking sensors and transmits the data to the FCDIM (display). Front & rear parking sensors have a different type of PAM module than rear only parking sensors. When retrofitting the front parking sensors the PAM module also needs to be replaced.
Without the wiring and front sensors connected a PAM module that supports both front and rear parking sensors generates DTC codes and disables the complete parking sensor system.
After front parking sensors are retrofitted it is a relative small step to also retrofit the Active Park Assist (autoparking) functionality. Next to the front & rear parking sensors the Active Park Assist system only requires the correct switch assembly with autoparking button and 2 different rear ABS sensors (Autoparking uses different ABS sensors which recognise the rotating direction of the wheels).
After all parts are installed you only have to reconfigure the particular settings in the Central Car Configuration of the car. This can be done with a suitible diagnostic system. For example a generic ELM327 interface and the free FoCCCus or Forscan software.
https://www.fordownersclub.com/forums/topic/98037-front-parking-sensor-on-focus-mk3/
RS Edition.
FPM375 Rocks
The rest of the “M” maps suck