DTC P0031, DTC P0032, DTC P0051 Or DTC P0052: Ho2S1 Heater: Description
WARNING: This page is about a different car, the 2003 Nissan Altima. However, it is still accessible from the selected car via links, so may be relevant.
ECM performs ON/OFF duty control of HO2S1 heaters based on engine speed and engine coolant temperature. The duty percent varies with engine coolant temperature when engine is started.