DTC P1706: Park/Neutral Position Switch: Description
WARNING: This page is about a different car, the 2002 Nissan Sentra. 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.