Abstract: A test light tool is provided for indicating electrical potential of a test surface of a vehicle D.C, electrical circuit. The test tool comprises a tool body, first, second and third LEDs disposed within the tool body and an indicator circuit connected to the LEDs. First and second connectors are provided, each having a first end connectable to the indicator circuit, and a second end connectable to one of first and second connection surfaces of the vehicle electrical circuit. A probe is provided having a first end in electrical communication with the indicator circuit and a second end extending from the tool body, and engagable to the test surface. The indicator circuit is operative to illuminate the first LED when the connector second ends exhibit an electrical differential therebetween sufficient to power the indicator circuit. The indicator circuit is further operative to selectively illuminate one or both of the second and third LEDs when the probe tip is engaged to the second surface.

Abstract: 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.

Abstract: A scan tool is provided which comprises a housing which houses a display and six mode buttons. The scan tool is communicable with an OBD of an automobile and provides information retrieved therefrom to a user of the scan tool in an efficient and effective manner. In particular, the display displays a plurality of information on one screen. For example, the display may display information related to I/M Monitor Status simultaneously with MIL status, stored, pending or historical codes. Further, the scan tool allows the user to switch between modes by depressing the mode button of the desired mode without having to manually exit the current mode and manually enter the desired mode.

Abstract: 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.

Abstract: There is provided a compression gauge assembly for diagnosing pressure variances of an engine cylinder(s). The gauge assembly comprises a gauge sensor in communication with the engine cylinder(s). The gauge sensor is operative to detect compression stroke pressures within the cylinder(s). A gauge controller is in communication with the gauge sensor. The gauge controller includes a comparator circuit operative to compare detected compression stroke pressures within the cylinder(s) and to derive the pressure variances therebetween. A gauge display is in communication with the gauge controller for displaying the derived pressure variances.

Abstract: There is provided a compression gauge assembly for diagnosing pressure variances of an engine cylinder(s). The gauge assembly comprises a gauge sensor in communication with the engine cylinder(s). The gauge sensor is operative to detect compression stroke pressures within the cylinder(s). A gauge controller is in communication with the gauge sensor. The gauge controller includes a comparator circuit operative to compare detected compression stroke pressures within the cylinder(s) and to derive the pressure variances therebetween. A gauge display is in communication with the gauge controller for displaying the derived pressure variances.

Abstract: A tachometer used to measure a speed of an engine. The tachometer includes a pickup, a counter circuit, a conversion circuit, an automatic switching device, an indicator and a meter display. The inductive pickup may be disposed around a spark plug wire of the engine to generate a pulse signal in response to a current flowing through the spark plug wire. The pulse signals are then counted by the counter circuit and input to the conversion circuit therefrom. The conversion circuit typically includes a plurality of lookup tables, each having mapped information correlating the pulse signals to the engine speed for a particular number of engine cylinders. The automatic switching device is operative to call up alternate lookup tables, e.g. each time when the electrical system of the engine is turned on. The display may be display the number of engine cylinders called up by the automatic switching device and measured engine speed.

Abstract: A tachometer used to measure a speed of an engine. The tachometer includes a pickup, a counter circuit, a conversion circuit, an automatic switching device, an indicator and a meter display. The inductive pickup may be disposed around a spark plug wire of the engine to generate a pulse signal in response to a current flowing through the spark plug wire. The pulse signals are then counted by the counter circuit and input to the conversion circuit therefrom. The conversion circuit typically includes a plurality of lookup tables, each having mapped information correlating the pulse signals to the engine speed for a particular number of engine cylinders. The automatic switching device is operative to call up alternate lookup tables, e.g. each time when the electrical system of the engine is turned on. The display may be display the number of engine cylinders called up by the automatic switching device and measured engine speed.

Abstract: A method of displaying automotive diagnostic information is disclosed comprising connecting a code reader to a vehicle computer and communicating monitor status information and trouble codes to the code reader. Only those monitor functions that are supported by the vehicle are illuminated on the code reader, along with their status. Trouble codes communicated from the vehicle are also displayed, along with trouble code descriptors. All display functions are operative independent of any manual input to identify the type of vehicle being tested.

Abstract: A method of displaying automotive diagnostic information is disclosed comprising connecting a code reader to a vehicle computer and communicating monitor status information and trouble codes to the code reader. Only those monitor functions that are supported by the vehicle are illuminated on the code reader, along with their status. Trouble codes communicated from the vehicle are also displayed, along with trouble code descriptors. All display functions are operative independent of any manual input to identify the type of vehicle being tested.