A vehicle diagnostic data collector/analyzer compiles historical vehicle diagnostic data, including measured operating parameters from a number of different vehicles operating under a variety of normal vehicle operating conditions and vehicle component failure conditions, and performs statistical analyses on various vehicle type/operating condition combinations to establish operating parameter ranges corresponding to normal operating conditions and various failure conditions. The diagnostic data collector/analyzer also measures real-time operating parameters on specific test-subject vehicles and evaluates similarities and differences between the measured operating parameters and the established ranges, and correlates the test data with known operating conditions in order to diagnose potential failure modes of vehicle components.