A portable generator includes a CO sensor module to sense CO levels in the environment surrounding the portable generator. The CO sensor module senses high levels of CO and sends a signal to shut down the engine on the portable generator. The CO sensor module alerts the user by emitting an LED light whether the CO sensor module is functioning properly, improperly or if high CO levels are detected. The CO sensor module is removable from a control panel of the portable generator to be replaced or maintained by the user per a replacement or maintenance schedule.