A vehicle state tracker tracks the state of a vehicle during a diagnostic test sequence to eliminate redundant steps between diagnostic procedures. The vehicle state tracker maintains a list of preconditions required for each diagnostic procedure, reads a current vehicle state from a memory register and verifies the current setting of the vehicle state corresponding to a specific precondition. If the precondition is required and the current setting is not valid, the state tracker further formats a test preparation step corresponding to the precondition for display to instruct a vehicle technician to satisfy the precondition. Otherwise, if the precondition is not required and the corresponding setting is valid, the state tracker formats an instruction to reverse the corresponding vehicle condition. The state tracker additionally receives feedback indicating when a precondition has been satisfied or the corresponding vehicle condition has been reversed, and updates the vehicle state in memory.