I searched the forum and read the threads regarding TPMS on the Xterras. I recently upgraded my S rims to Pro-4X rims with TPMS installed. My former S rims had the black TPMS and the Pro-4X rims have the orange TPMS. Not sure what the differences are. However after driving about 35 miles on the highway, the TPMS light comes on. I pull over to the gas station to check the air and fill up accordingly and notice that the drivers side front and rear needed a little air. I filled them up to 35lbs then got back on the highway. About 35 miles or so again - the light comes on. I pull over and park. Turn the car off, then back on again - the light goes off. What seems to be the issue here? Faulty TPMS or???