Hi alan d;
E 28 code tells us that the ECM (Engine Contol Manager) is not receiving a signal from the camshaft's Hall effect sensor that is located in engine's timing cover just across from the alternator. There are two sensor adjacent to each other. The one closest to the alternator is the one that needs to be checked for loose or broken wires or a plug and socket not fully connected. If this truck is not equipped with protective under belly screens, it is highly possible that the fan has sucked up trash and done you bad things.