I did some searching but nothing conclusive. So my car hasn't been in range of my wheels with the tpms sensors for about a month and a half. Today we mounted the 4 wheels with the sensors back on the car and it doesn't detecting any of them. The spare is also out right now because I had the air tank and compressors installed in the tire well. Any idea why the sensors are all now not detecting? My friend said that he'd check the system for me when I get back to his shop. But prior to that any idea why this happened?

 

The TPMS might go into a sleep mode after an extended period of non-reporting sensors.

I expect that all will return to normal if you disconnect the car's battery for a few minutes and then reconnect it. Disconnecting the battery likely sets the TPMS to a default benchmark of 33 PSI so if you are setting a cold-inflation pressure different from that you would want to do the benchmark procedure.