Since I had used my entire bottle of sealant in a failed attempt to patch a tire, I was concerned after reading a couple posts on this site regarding possible damage to the pressure sensor in the affected wheel. Yesterday, I conducted a simple experiment. I lowered the pressure in the tire, which was plugged two weeks and 1000 miles ago, and still contains much of the sealant inside (what didn't shoot out of the hole in the tire). The dash sensor illuminated. I then used the little compressor that comes with the car to inflate the tire back to 34 psi. The low pressure light on the dash went off. Conclusion: the sealant supplied with the car should not effect the ability of a tire to sense pressures as designed.