You Either have a Broken wire or a bad connecion from your wiring harness to your ECU Recommend removing plug and testing wires for continuity and or voltage also check harness connection
as the dealer says 3500 llb when properly equipt
for the four cylinder engine it is underneath the air filter box. remove the wing nuts and plastic hose and pull the whole box up. on the left rear of the intake manifold you will see a cylinder like thing w/ a black top. it will have a tube connecting it to the exhaust. if you cant find it trace the tube from the exhaust to the valve. You might not need to replace it because the tube or EGR intake may have become clogged. spray some carb cleaner in there and get that gunk out.
Run your engine and put your hand underneath the valve, you should feel a rubber bladder, press on it, if your engine bogs down and wants to die you probably dont need a new one.