tpms

I go thru the whole exercise and after 1 do the last tire the system stops and nothing has been saved. Well within the 5 minutes. I do get 2 beeps after each tire.

Hopefully someone can shed some light on this. I had my '08 Envoy SLT in and had the snow tires put on. Mechanic relearned the sensors in the winter rims so everything would read right. The problem is now that while the pressures are reading right (well within proper pressures) it says LOW on...