Oxygen Sensor
WARNING: This page is about a different car, the 1996 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
Oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to Engine Control Module (ECM). The ECM may use the input signal to determine ignition timing (spark advance) and control fuel injection system. Some models may be equipped with more than one oxygen sensor and a sub-oxygen sensor. On some models, a heated oxygen sensor may be used. On heated oxygen sensors, a heater is used to warm the oxygen sensor to improve oxygen sensor detection operation. The heater is controlled by the ECM.