1. An electronic control device for monitoring the idle of a diesel engine and idling-down the diesel engine comprising: an electronic control unit (ECU) associated with the diesel engine; a control area network (CAN) that establishes electronic communication with the ECU; a user interface, the user interface comprising a housing; a microprocessor; programmable software to determine a plurality of operational parameters of the diesel engine and to institute electronic commands to the ECU via the CAN; a visual display; and a plurality of input means; wherein the ECU communicates with the user interface via the CAN in conformance with the J1939 protocol; and wherein the diesel engine idle is monitored and idled-down in accordance with a pre-programmable scheme.