DTC P0031: Ho2S1 Heater Control Circuit Low - Bank 1, DTC P0032: Ho2S1 Heater Control Circuit High - Bank 1, DTC P0051: Ho2S1 Heater Control Circuit Low - Bank 2 &/Or DTC P0052: Ho2S1 Heater Control Circuit High - Bank 2: Description
WARNING: This page is about a different car, the 2002 Nissan Maxima and 2002 Infiniti I35. However, it is still accessible from the selected car via links, so may be relevant.
The ECM controls on/off operation of HO2S1 heaters based on engine speed. When engine speed is less than 3600 RPM, HO2S1 heaters are turned on. When engine speed is more than 3600 RPM, HO2S1 heaters are turned off.