I just got back from the beach where I did a lot of beach driving. I would air down to about 20 lbs and when I would air back up the TPMS light would immediately go off. Great, no problems, works exactly as it should. I aired down and back up probably 5 or 6 times during the week with no issues. So we come home and Monday morning I go to work, the TPMS light comes on. I check the pressures and everything is fine but the light doesnt go off. Now the first thing I did when I got home was go through a car wash to get the salt spray and sand off. For those of you that are land locked and may not have much experiance with the ocean, salt spray is nasty and sticky and sand just sticks right to it. So as soon as I could, I got her in the detail bay at work and took the power washer to it. I did the underneath real well and when I was done, the light was off and has not been back on this week. I dont know if the sand could affect the sensors, but it is something to keep in mind.