Circuit Description
WARNING: This page is about a different car, the 2006 Suzuki Reno and 2006 Suzuki Forenza. 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 C62 and C4. The Heated Oxygen (HO2) 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 HO2 sensor is like an open circuit and produces no voltage when it is below 360 °C (600 °F). An open HO2 sensor circuit or a cold HO2 sensor causes "Open Loop" operation.