DTC P0031, DTC P0032, DTC P0051 Or DTC P0052 : Description
WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
The ECM controls on/off operation of HO2S 1 heaters based on engine speed. When engine speed is less than 3600 RPM, HO2S 1 heaters are turned on. When engine speed is more than 3600 RPM, HO2S 1 heaters are turned off.