Same fault code P1706 for the park/neutral position switch, found only on automatic models, and the neutral position switch, found only on manual models. Different switch, different location, same fault code. Your neutral position switch is located on the right side of the transmission toward the back end. Here's a Nissan Parts Deal page with a few diagrams to show you where it is. >>>
https://www.nissanpartsdeal.com/parts-l ... pnc=32006M The part number is either 32006-23U6A or 32006-32G2A depending on your model options. You can plug in your VIN at Nissan Parts Deal to be sure of the right part for your '01. Before replacing anything, I would first check the connector plug to this switch to be sure the contacts are clean, dry, and not corroded. It gets very messy back there from water and dirt kicked up off the road. It might be just poor contact in the plug.