Abstract: The present disclosure provides a vehicle occupant detection and alert system including an onboard apparatus including a controller operably connected to an occupancy sensor, an environment sensor and a transceiver. The controller generates a signal indicating that an occupant is present. A mobile communication device is operably connected to the transceiver. The mobile communication device includes a processor which upon execution of instructions performs the steps including: receiving a signal from the controller indicating that an occupant is in the vehicle, responsive to an alert condition, initiating a first alert mode, wherein a first notification is generated and the functionality of the mobile device is restricted; and generating a prompt to enter a code to acknowledge the first notification, wherein the functionality restriction is removed in response to entry of the code.