DTC P1767: High And Low Reverse Clutch Solenoid: Description
WARNING: This page is about a different car, the 2012 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
High and low reverse clutch solenoid valve is controlled by the TCM in response to signals sent from the transmission range switch, output speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.