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) continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitoring period, the PCM counts the number of rich to lean and lean to rich transitions and adds the amount of time it took to complete all transitions. With this information, an average time for each transition can be determined. If the average response time is too slow, a DTC P0133 will set. A lean to rich transition is indicated when HO2S voltage changes from less than 300 millivolts to more than 600 millivolts. A rich to lean transition is indicated when the HO2S voltage changes from more than 600 millivolts to less than 300 millivolts. An HO2S that responds too slowly is likely to be malfunctioning and should be replaced. DTC will set if HO2S bank 1 sensor 1 lean-to-rich or rich-to-lean average transition response time during the sample period is more than 220 milliseconds.