Patent ID: 7751955

Claim:
A computer-implemented method of analyzing vehicle test data, comprising: compiling, via a processor of a diagnostic device, a collection of historical test data points which includes a plurality of operating parameter measurements recorded by an individual vehicle's onboard computer, wherein the diagnostic device and the vehicle are separate but connectable objects; correlating, via the processor, each historical test data point with an operating condition to produce entries of a diagnostic case history; grouping, via the processor, the entries of the diagnostic case history by operating condition; defining, via the processor, a range corresponding to the operating condition of a vehicle type based on the collection of test data points of the entries of the diagnostic case history grouped by operating condition; and diagnosing, via the processor, a vehicle component failure mode based on the range corresponding to a failure condition; wherein the operating parameters are selected from the group consisting of: an ignition switch position, an engine run condition, a throttle position, an engine speed, a vehicle speed, a test equipment connection, a vehicle electrical connection condition, an ambient air temperature, an engine inlet temperature, an engine lubricant pressure, an engine lubricant temperature, an engine lubricant level, an engine coolant temperature, an engine coolant specific gravity, an engine exhaust gas temperature, an engine exhaust gas content, a transmission setting, a brake pedal position, a parking brake position, a brake fluid pressure, a fuel level, a fuel supply pressure, a battery voltage, a battery charging system voltage, a battery charging system current, an ignition voltage, an ignition current, and an engine cylinder compression.