1. A method comprising: receiving system fault codes, component fault codes, and failure modes; generating a first level model comprising first level causal relationships and first level causal weights between the system fault codes and the component fault codes; generating a second level model comprising second level causal relationships and second level causal weights between the component fault codes and the failure modes; combining the first level model and the second level model to generate a graphical model; and determining, using the graphical model, one or more probability inferences.
1. A method comprising: receiving system fault codes, component fault codes, and failure modes; generating a first level model comprising first level causal relationships and first level causal weights between the system fault codes and the component fault codes; generating a second level model comprising second level causal relationships and second level causal weights between the component fault codes and the failure modes; combining the first level model and the second level model to generate a graphical model; and determining, using the graphical model, one or more probability inferences. 3. The method of claim 1 , comprising: receiving one or more vehicle specific system fault codes and one or more vehicle specific component fault codes; determining one or more high probability failure modes based on the probability inferences, wherein determining, using the graphical model, one or more probability inferences comprises determining conditional probabilities based on the vehicle specific system fault codes, the vehicle specific component fault codes and the graphical model; and outputting high probability failure modes to a user.