DTC P1706: Park/Neutral Position Switch: Description
WARNING: This page is about a different car, the 2002 Nissan Xterra and 2002 Nissan Frontier. However, it is still accessible from the selected car via links, so may be relevant.
When the gear position is "P" (A/T models only) or "N", Park/Neutral Position (PNP) switch is on. ECM detects the position because the continuity of the line (the "on" signal) exists.