An automotive electronic control system configured to detect and signal the presence of a passenger left unattended in a motor vehicle based on signals from an automotive sensory system ( SENS) comprising: - one or more radar sensors arranged in the passenger compartment of the motor vehicle to allow the presence of one or more passengers sitting on one or more seats of the motor vehicle to be determined, - one or more door sensors associated with one or more doors of the motor vehicle to allow locking and unlocking, and opening and closing, of one or more doors of the motor vehicle to be determined; - one or more seat sensors associated with one or more seats of the motor vehicle to allow the presence of one or more passengers sitting on one or more seats of the motor vehicle to be determined; - one or more safety belt sensors associated with one or more safety belts of the motor vehicle to allow fastening and unfastening of one or more safety belts to be determined; the automotive electronic control system is configured to: - receive signals from the automotive sensory system ( SENS); - determine when the doors of the motor vehicle are unlocked; - when the doors of the motor vehicle are determined to have been unlocked, determine whether a door of the motor vehicle has been opened for a sufficient length of time compatible with a passenger getting in the motor vehicle; - if a door of the motor vehicle is determined to have been opened for a sufficient length of time compatible with a passenger getting in the motor vehicle, signal a potentially hazardous situation due to the presence of a passenger in the motor vehicle according to a first signalling mode or by means of a first signalling device; - determine when the door of the motor vehicle has been closed; - when the door of the motor vehicle is determined to have been closed, determine occurrence of a switch from a key-on state to a key-off state of the motor vehicle; - if a switch from a key-on state to a key-off state of the motor vehicle is determined to have occurred, activate one or more radar sensors to check for the presence of the passenger in the motor vehicle; - if the passenger is determined not to be on the motor vehicle based on the radar sensors, interrupt the signalling of the potentially hazardous situation in the motor vehicle; - if instead the passenger is determined to be on the motor vehicle based on the radar sensors, signal the presence of the passenger in the motor vehicle according to a second signalling mode and/or device different from the first signalling mode and/or device. - one or more radar sensors arranged in the passenger compartment of the motor vehicle to allow the presence of one or more passengers sitting on one or more seats of the motor vehicle to be determined, - one or more door sensors associated with one or more doors of the motor vehicle to allow locking and unlocking, and opening and closing, of one or more doors of the motor vehicle to be determined; - one or more seat sensors associated with one or more seats of the motor vehicle to allow the presence of one or more passengers sitting on one or more seats of the motor vehicle to be determined; - one or more safety belt sensors associated with one or more safety belts of the motor vehicle to allow fastening and unfastening of one or more safety belts to be determined; - receive signals from the automotive sensory system ( SENS); - determine when the doors of the motor vehicle are unlocked; - when the doors of the motor vehicle are determined to have been unlocked, determine whether a door of the motor vehicle has been opened for a sufficient length of time compatible with a passenger getting in the motor vehicle; - if a door of the motor vehicle is determined to have been opened for a sufficient length of time compatible with a passenger getting in the motor vehicle, signal a potentially hazardous situation due to the presence of a passenger in the motor vehicle according to a first signalling mode or by means of a first signalling device; - determine when the door of the motor vehicle has been closed; - when the door of the motor vehicle is determined to have been closed, determine occurrence of a switch from a key-on state to a key-off state of the motor vehicle; - if a switch from a key-on state to a key-off state of the motor vehicle is determined to have occurred, activate one or more radar sensors to check for the presence of the passenger in the motor vehicle; - if the passenger is determined not to be on the motor vehicle based on the radar sensors, interrupt the signalling of the potentially hazardous situation in the motor vehicle; - if instead the passenger is determined to be on the motor vehicle based on the radar sensors, signal the presence of the passenger in the motor vehicle according to a second signalling mode and/or device different from the first signalling mode and/or device.