Air pressure Warning Light Sentra 2008

Did you physically check the pressure with a gauge or are you just going by the way the tire "looks".

The light comes on when the pressure of the tire drops below 28 psi, when the pressure is properly corrected the TPM (tire pressure monitoring) system will shut off the light.

Follow up-

I bought a new pressure gauge, rechecked all tires and verified 33 lbs in each tire that my other gauge had also read. Light still on. Filled tires to 38 lbs and light went off. Backed tires down to 35 lbs, will see if light goes back on.

It seems the warn>Did you physically check the pressure with a gauge or are you just going by

Might be unrelated. But! At work we have a Dodge Sprinter with monitoring tire pressure as well. In the owner's manual it says that you must not change the cap on the tire valve from plastic to metal, as it may interferes with the signal.