An engine control system (10) operates off a microprocessor of an engine control module, ECM (62), which will automatically start a combustion engine (12) upon any one of a series of enabler signals (68, 67, 70) indicative of low battery voltage, low cab temperature and / or low engine temperature. The system (10) also includes safety measures which will override the automatic starting of the engine. For instance, the vehicle will not automatically start if a vehicle speed is detected, if the parking brake is not set, if the ignition key (50) is not in the “on” position, or if the hood (56) is open. Moreover, the system (10) is configured not to start if the fuel level is low, thus preventing an unintended depletion of fuel which could strand the vehicle and operator.