Particular attention is required when addressing an oxygen or air/fuel ratio sensor since the pigtail and the electrical connector are permanently included, and their removal will destroy the sensor. Grease, dirt, and other such compounds must not come in contact with the electrical connector as well as the louvered end of the sensor and no cleaning solvents are to be used and the sensors should not be roughly handled. Make sure that the silicone boot has been fitted in the right manner to avoid cases where it melts, and to offer the right services. Because of their locations in the exhaust manifolds or pipes that shrink when cool and can be tight when cold, they can be tight to unscrew-briefly cranking the engine will help. Make sure the ignition key is off, and then safely lift the car with jackstands always in place. In V6 variants, there are four oxygen sensors and the upstream ones are mounted at the outlet portions of the exhaust manifolds, above the upstream
Catalytic Converters. To replace an upstream sensor, look for it, follow the electrical lead to the connector, depin or pull it and back off the sensor using a wrench while applying anti-seize to the threads before tightening with a torque wrench. The same procedure can be applied to downstream sensors that are located in the front exhaust pipe assembly upstream of the downstream catalysts. For four cylinder there are two sensors, front exhaust sensor is mounted on the front exhaust pipe near the exhaust manifold flange. The replacement procedure also applies to the V6 models but anti-seize compound should be applied and the sensor tightened to the correct torque.