Firstout shutdown tracing for fuel processor control system

A method and apparatus for determining which condition in a fuel processor has initiated a shutdown of the fuel processor are disclosed. In general, the apparatus generates a plurality of shutdown initiator signals, each corresponding to one of a plurality of shutdown conditions and indicating whether such condition is present. The shutdown initiator signals are read within a predetermined window. At least one of the read shutdown initiator signals indicates that a corresponding first shutdown condition has occurred and identifies the corresponding first shutdown condition as the firstout.