TPMS Losing Signal
First time posting, hoping someone has dealt with this before and can offer a solution. 2007 Limited Grand Cherokee with Premium TPMS (displays the actual tire pressure for each wheel). I've had 2 new (OEM) TPMS replaced on my front 2 wheels ( new tires as well ). The sensors were reprogrammed by the dealer prior to leaving. After driving approximately 15 minutes at highway speed the TPMS warning light appeared and the tire pressure registered "----". The warning light disappeared after ~5 minutes and the TPMS registered a PSI again. This happened twice on an hour drive.
I took the car back in and had them reprogrammed again as the tech stated the computer didn't have the correct sensor ID and it should be good now. Again, after driving for 15 minutes the TPMS monitor showed "----" as the tire pressure and then regained a signal a few minutes later (and dropped it again).
Again, took it back to the dealer. In an effort to eliminate a transponder failure or sensor failure we moved the wheels with the new sensors to the rear and the wheels with the original sensors to the front. Under this assumption, if the sensors flatlined again, it's a problem with the sensor and not the transponders.
The new sensors flatlined again (now the rear wheels). The dealer then replaced those sensors with 2 additional sensors and it's still losing the signal. To clarify. When they flatline, they don't register for 10 minutes or so and then are picked back up. So they don't permanently drop them.
According to the Dealership, these are the correct sensors. They are a little stumped at this point and have my car for a day to diagnose it. There is obviously a communication failure with the sensors. Any idea what would cause this? Compatibility issue? Fixes?
Any suggestions or recommended solutions are appreciated!!