Recently the tire pressure displays —- (3 dashes) for each tire, I have not replaced any TPMs but supposedly they were serviced when the tires were replaced about 2000 miles ago. I have rest the tire pressure monitor but this is the pressure display? I have tried the turn on/off like the manual says. Any thoughts beforeI pay the dealer?

 

Four "---" mean the car is reading pressures from the sensors but cannot determine the sensor locations relative to the car. This often happens with aftermarket sensors. Otherwise the TPMS system is working and will still alert you if one of the tires is low on air (will illuminate the yellow TPMS light).

How much was the TPMS "servicing fee"? If if was about $50 per wheel then it probably means the sensors were replaced with aftermarket ones.

The reset button only tells the car to remember the current pressures and keep them as the baseline.