An instrument is provided which is in electronic communication with an on board diagnostic system (OBD) of an automobile. The instrument selectively queries the OBD with batch requests for the purpose of reducing a processing load placed on the OBD PCM. The instrument obtains numerous operating conditions through the OBD, and displays the operating conditions in an intuitive format. The operating conditions may be grouped into five different modes, and the five most relevant operating conditions within each mode may be displayed on the monitor either by default or through customization by the user.