Toyota 89467-41030 Oxygen Sensor

OBD-II equipped vehicles with C engine management systems can check the validity of the feedback loop of the oxygen sensor with the PCM with the help of upstream oxygen sensor or air/fuel sensor prior to the catalytic converter and the downstream oxygen sensor located post the converter. The upstream sensor is mounted on the exhaust manifold and the downstream sensor which is heated is installed after the catalytic converter. While distinguishing between oxygen sensors and air/fuel sensors, one should note that the air/fuel concepts function differently, as for the air/fuel sensor, the output voltage depends on the ratio of air to fuel and does not change at the stoichiometric point. The permanently connected pigtail and electrical connector must not be damaged when servicing these sensors; dust and grime should not get in contact with the connector or the end of the sensor; nothing should be poured on these sensors; and they must be handled carefully. Before replacing a sensor one has to warm the engine so as make removal easier, the negative terminal of the battery should be removed and the sensor harness should be reached. The upstream sensor can be easily replaced with out lifting up the car while the downstream sensor will need the car to be supported on jackstands. It is suggested that one should use a slotted socket to do it, anti-seize compound should be applied to the threads of the sensor before assembly. Finally the sensor is safely locked in place and the electrical connector joined back, the vehicle should be lowered, as well as tested on the road so that there is no trouble code existing.