Object Detection

The liftgate control module continuously monitors power liftgate operation and calculates its location and direction of travel using 2 hall effect sensors that are part of the gear motor assembly. The hall effect sensors are 3 wire sensors and are supplied with a 5 volt power circuit, ground and signal circuits from the liftgate control module. The hall effect sensor signal circuits are referenced from battery voltage within the liftgate control module and pulsed low by the hall effect sensors.

The power liftgate system uses a secondary object detection method which consists of object sensors fixed to both sides of the liftgate near the seal area. The object sensors consist of an internal fixed resistor and normally open switch contacts which when closed will bypass the resistor. The signal circuit is supplied 5 V through a resistor and monitored within the liftgate control module, and during normal power liftgate operation the signal circuit should remain a fixed value. When an object presses one of the sensors the contacts close and the resistor is bypassed causing the signal circuit voltage at the module to go low.