Abstract: A microprocessor is used to control various components of a carpet cleaning machine to improve its functionality. In various aspects of the invention, the microprocessor is software controlled, and can provide sequential operating instructions to the operator, enforce start-up and shut down sequences, store an electronic record of operating parameters for future use, provide auto--and remote diagnostics, and provide remote control. In another aspect of the invention the microprocessor can affect the operation of the entire system by dynamically controlling the speed of the motor. In another aspect of the invention, a more effective muffler can be attached to the exhaust of the motor, thereby greatly reducing the noise level. In still other aspects of the invention, the microprocessor can operate an ignition kill switch to the motor, solenoid and/or clutch controls for the fluid and air pumps, an energy cutoff switch for the heater, and software updates via modem.