If you build a Ford I couldn't get it to work no matter what I did to my 2008 Ford. Finally found out that if you hold it up to the valve and switch the mode to hm and then back to ford the sensor will activate as soon as you switch it to ford but if you don't have it against the tire at that moment of switching it will not activated. it's almost like he's going through the frequencies one by one until he gets what he wants. Mine happens to be the first thing it tries when you switch it to Ford.