Toyota 89467-41011 Air Fuel Ratio Oxygen Sensor

First off, all vehicles are equipped with On-Board Diagnostics II (OBD-II) engine management systems that include oxygen sensors and air/fuel sensors to verify the accuracy of the feedback loop between the oxygen sensor and the PCM. These sensors are placed before and after the catalytic converter to help control the efficiency of the converter. In fact, Camry models with four-cylinder engines have one oxygen sensor and one air/fuel sensor, while V6 engines have three sensors. Also, the main sensors are located in the exhaust manifolds, while the secondary sensor is placed after the catalytic converter. It is also important to note that the oxygen sensors monitor the oxygen in the exhaust stream to determine the air-to-fuel ratio, while the air/fuel sensors send feedback about alterations. Also, proper operating temperature, electrical connections, outside air supply, and use of unleaded fuel are important for the sensors. Finally, the silicone boot must be installed carefully to prevent damage and ensure proper function.

Disconnect the battery, unplug the electrical connector, unscrew the sensor from the exhaust manifold, apply anti-seize compound to the threads, and install the new sensor.

The purpose of On-Board Diagnostics II (OBD-II) engine management systems in vehicles is to verify the accuracy of the basic feedback loop between the oxygen sensor and the PCM.

The PCM will set a diagnostic trouble code if this condition occurs at 1,500 or more rpm after the engine reaches normal operating temperature.

Because the A/F sensor is installed in the exhaust manifold or pipe, which contracts when cool, it may be difficult to loosen when the engine is cold. Run the engine for a minute or two before attempting to remove it.