Method and system for detecting a presence of a block heater in an automobile

The present invention relates to a method and system for detecting a presence of a block heater in an automobile. In one embodiment, an automobile includes an engine, a radiator, an engine coolant temperature ("ECT") sensor, and/or an engine control unit ("ECU"). The radiator delivers coolant to the engine to cool the engine. The ECT sensor is located in a path of the coolant and determines ECT data. The ECU determines a temperature difference between a current maximum temperature of the engine coolant temperature data at a first time period and a current minimum temperature of the engine coolant temperature data at a second time period after the first time period. When the temperature difference is greater than a predetermined temperature threshold, the ECU determines that the block heater is present When the block heater is present, the ECU masks any engine malfunction detections.