I had this problem and was told I needed a better tire seal because of the wheels.
The tire place sealed them better, but I still have issues with that low pressure light not wanting to go off especially on cold days after I fill them.
There is a reset button to the left of the steering wheel on the panel.
Here are directions. It's the same for our Matrix:
https://www.youtube.com/watch?v=OPLRCmF3yF0