A system used to protect the occupants of a stationary motor vehicle, particularly unattended children and pets, from dangerous conditions occurring within the vehicle. The system comprises a sensor which senses dangerous environmental conditions such as high temperatures within the vehicle. In the preferred embodiment, the sensor is used with a transmitter to continuously transmit sound detected within the vehicle passenger compartment as well as transmitting information about any dangerous conditions which occur to a remotely located person. In a second embodiment, dangerous conditions trigger an alarm attached to the vehicle. The alarm amplifies the sound detected within the vehicle, such as a crying child, or a barking dog, and also produces a standard alarm sound alternated with an amplified voice declaring the dangerous condition. In a third embodiment, a sensor module attached to a wireless telephone informs a remotely located person of the dangerous condition through another wireless telephone or a pager.