I'll be calling them. This morning I drove back from a state park. At one point I pulled into a rest stop and shut the truck down. This turns off the monitor. Upon restarting the truck I set the odometer to "0"
Within 6 miles two of the sensors were reading. At 17 - 19 miles, four more came on line. I arrived home and the final two were not on line....26 miles later.
One is a right front tire. About 8' from the monito. The other is a left rear tire on the trailer (19' trailer), putting this sensor about 18' from the monitor. This sensor has always been the last to come online, but it usually will after about an hour.