Circuit Description
WARNING: This page is about a different car, the 2006 Suzuki Verona. However, it is still accessible from the selected car via links, so may be relevant.
The Engine Control Module (ECM) supplies a voltage of about 0.45 V between the ECM terminals K11 and K12. The Oxygen (O2) sensor varies the voltage within a range of about 1 V if the exhaust is rich, down to about 0.1 V if the exhaust is lean. The O2 sensor is like an open circuit and produces no voltage when it is below 300 °C (600 °F) open O2 sensor circuit or a cold O2 sensor causes "Open Loop" operation.