DTC P0030: Ho2S Heater Control Circuit (Sensor 1): Description
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
The heating elements inside the heated oxygen sensors (HO2S) minimize the time required for the sensors to reach operating temperature and then provide an accurate voltage signal. The PCM controls the HO2S heater operation with a low side driver. The HO2S 1 heater diagnostic monitors the current draw through a high side driver that also supplies power to the HO2S bank 1 sensor 1 heater. If the powertrain control module (PCM) detects that the HO2S bank 1 sensor 1 heater high control circuit condition is incorrect, DTC P0030 will set.