They worked for several days and even correctly gave a 'low pressure' warning (the tire dealer only set it to 30psi). I then intentionally deflated the two rear tires to go drag racing (40psi to 22psi). I've done this many times with my stock gauges and never had a problem after inflating my tires. Now I get the message "inactive" and am looking for a solution. Update: They are working again. Now 5 days in a row. Let's see how long this lasts.