Program is a set of instructions that can be accepted by the microprocessor, the program introduces the microprocessor into a judgment state. For example, a program can retrieve information sent by a sensor through the microprocessor and then tell the microprocessor what to do with that information. Finally, the program will instruct the microprocessor to trigger an output control device such as a relay or solenoid. Various memories hold programs and other automotive data. The microprocessor uses this data to perform calculations.