A diagnostic test sequence optimizer includes a diagnostic test selector that determines a group of diagnostic test procedures related to a specific symptom and vehicle type from a pool of diagnostic procedures. A failure mode analyzer then selects one or more factors that can affect resolution of a vehicle operational problem and performs a failure mode analysis to quantify a comparative utility of the individual tests, and a factor weighter assigns a weight to each of the factors. A vehicle receiver receives information regarding the history of the test subject vehicle, and a sequence optimizer places the diagnostic test procedures in an optimized sequence in accordance with the comparative utilities of the individual diagnostic procedures, user preferences and a Failure Mode and Effects Analysis compiled by the manufacturer of the vehicle.