Circuit Description
WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The Heated Oxygen Sensor (HO2S) is used for post catalyst monitoring. The HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. Ground is provided to the heater by a ground circuit. This diagnostic will only run once per ignition cycle. If PCM detects that HO2S 2 time to become active was too long, DTC P0141 will set.