Some words of warning, when servicing an oxygen sensor, one must be careful, as it is located in the exhaust manifold or pipe, and when cold, the metal contracts, and becomes incredibly tight; a five-minute warm up assists in protecting the sensor or the threads to which the sensor is attached from becoming damaged, but be careful not to burn yourself in the process. All models have two oxygen sensors: both upstream and downstream. In 1.5L engines, the upstream is located at turbocharger outlet elbow, the downstream is located beside the
Catalytic Converter. For 2.0L engines the upstream sensor is situated at the turbo outlet just ahead of the catalytic converter, while the downstream sensor is found in the exhaust pipe right after it. In 2.5L engines the upstream sensor is placed in the exhaust manifold, and the downstream sensor is located under the catalytic converter. When the oxygen sensor has to be serviced, it is important not to damage the pigtail which is permanently connected to it as well as the electrical connection; it is also important not to expose the connector and the sensor end to contaminants, it is also prohibited to use solvents when cleaning the sensor; the handling of the sensor must always be gentle and care should be taken to ensure the silicone boot is positioned correctly so that it will not melt or cause The upstream oxygen sensor has to be taken off by first, taking off the engine cover, disconnecting its electrical connector and then unclipping it before it is pulled off. In the case that one can reinstall the old sensor, one must use anti-seize compound on threads; for the new sensor this is not required since they coat it themselves. Installation is done in a reverse manner with caution that the screws of the sensor are tightened to the recommended torque. To get to the downstream oxygen sensor, lift the vehicle safe, and as you get to the connector beside the heat shield and ducting for 1.5L turbo, unplug the connector, unscrew the sensor with the vehicle off, and if you are using the old sensor, use the anti-seize compound. As with removal, installation is the exact opposite and the sensor is torqued to the correct level.