After checking values, I would follow guidance provided by LACHAU, we all know it's a PITA to backprobe connectors but not everyone has all the breakout boxes. I'm concerned mostly with the connectors at the EGR housing that act as a go-between. Verify your circuit integrity from end to end, yes, all the way to the ECM. Be EXTREMELY CAREFUL not to spread the pin sockets in the cavity. I always use a terminal removed from an old sensor and carefully check for drag while inserting and withdraw. While you have your measuring equipment hooked up, twist and manipulate the harness along it's path. Pay particular attention to right at the connectors and at each P clamp. Your looking for wires broken within the insulation(common Deutsch connector problem) and chaffing at clamps and bends. When measuring the circuit, don't forget to measure against the neighboring circuit for cross-bleed. Good luck