Toyota 89467-02020 Oxygen Sensor

All vehicles with OBD-11 engine management systems can check the correspondence of the feedback loop from the oxygen sensor to the PCM with the help of an upstream oxygen sensor or air/fuel sensor before the catalytic converter and a downstream one behind it. The PCM monitor the efficiency of the converter through taking sample of exhaust gas from the two locations and can determine when the converter is likely to fail. The primary one is mounted in the exhaust manifold while the second one is after the catalytic converter. Special attention should be paid to it, since the service of these sensors has a permanently installed pigtail with the electrical connector which should not be disconnected and, accordingly, the contaminants are prohibited to approach the connector and the end of the sensor. Special cleaners should not be used and the sensors should not be dropped or handled roughly. Correct positioning of the silicone boot plays a very crucial roll If not well installed the gadget is likely to have poor performance. This can be a problem when replacing a sensor where it can be quite tight when the engine is cold to get loose, therefore the need to briefly rev the engine. For the downstream sensor, the car has to be lifted in canton mode and ought to be grounded also the electrical plug has to be disconnected. This hose can be removed/changed without lifting the vehicle up and this can be done by following the harness to the connector. It is advised to use slotted socket for removal, and anti-seize compound should be used on the threading of the sensor such that it will not touch the end of the sensor. The electrical connector should be reconnected and during test drive no trouble code should be identified.

In cold conditions, it's advisable to briefly warm the engine before replacing the oxygen sensor to prevent potential sensor damage.