It does have a sensor, and it is just too sensitive, so quite often I push the close button, run into the car (it rains), only to find out it did not close and I have to run out, look for the button (because the gate is opened just slightly at that point), press it again, make sure it closes, etc... Too much.

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His : 2013 X5 3.5d Deep Sea Blue/Black/Aluminum with ALL packages, 20" 214"s, running boards, Adaptive Drive, Spare Tire, BMW Apps
On Order : 2016 X3 3.5 MSport Silver/Mocha with DHP, CW, Prem, Tech, DA, Lighting

Hers : 2015 328xi MSport Silver/Red

Prior:
2008 X5 4.8
2011 X5 3.5d
2010 335 xDrive
2013 335 xDrive