Circuit Description
WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) supplies a bias voltage of about 450 millivolts between the Heated Oxygen Sensor (HO2S) high signal circuit and the HO2S low reference circuit. When measured with a 10 megohm Digital Multimeter (DMM), this may display as low as 350 millivolts. The oxygen sensor signal varies from about 800 millivolts when exhaust is rich, to about 50 millivolts when exhaust is lean. If HO2S 1 voltage remains at or near the 450 millivolts bias for an extended period of time, DTC P0134 is set.
If the signal frequency of HO2S bank 1 sensor 1 indicates that the sensor is active and the system is operating in Closed Loop, but the voltage or amplitude of the signal remains within a calibrated range, DTC P0130 will set.