It's probably bad but it"s not for propane, its for CO carbon monoxide. nuting to do with propane. It will alarm if you have a faulty furnace, generator or someone running a gas engine nearby. Maybe the stove to.
That said, they do go bad and can be replaced. Some of them have a replaceable module if it has expired you can just try changing that.
2007 Chevy 2500HD Classic LBZ Duramax/Allison (Stock)
2005 Bigfoot 1500C8.2 AWESOME