Yes it's standard on Limited and SRT 6 but not available on the base. When it detects i think a 20% pressure drop from the standard air pressure setting for any tire front or back, a yellow light comes on in the left side of your instrument cluster with a picture denoting low tire pressure. However the system is pretty lame as opposed to that of the 350Z which tells you the tire pressure for front and rear in digital readouts, ours only lights up this weird symbol that's supposed to look like a tire with low pressure and then you have to go out and inspect each tire to see which one is not inflated properly.

The sensors are mounted inside each rim and are of fragile plastic. Maybe you hit a large bump and one came loose and the light is coming on. If it goes out for a while then comes on, you might have a small leak on a tire from a nail or etc... Also make sure you're checking your tire pressure when cold not when warm. Warm tires expanding give you higher readings and if you're reducing air pressure when warm, then when the tire gets cool and drops in air pressure you'll be below the factory setting for the TPM system and the light will come on.