How to Replace the o2 Sensor on Hyundai Santa Feby Alibaster Smith
The O2 sensor on a Hyundai Santa Fe measures the air to fuel ratio to make sure that the vehicle doesn't burn too much gasoline (running "rich"), or to prevent the engine from burning too little (running "lean"). The O2 sensor relays information to the vehicle's computer allowing it to adjust the fuel mix as necessary. This is done to make sure that the Santa Fe gets the best fuel economy, while at the same time reducing emissions and optimizing power output.
Let the Santa Fe cool down. If you have just run the engine, the entire system should cool for several hours before attempting to work on the exhaust system where the O2 sensors are located.
Place the floor jack under the Santa Fe and jack up on the front jack point located behind the radiator.
Place a jack stand under each of the front pinch welds located directly under the driver and passenger side doors on the underside of the vehicle.
Locate the O2 sensors. There are four oxygen sensors on the Santa Fe (usually). There are 2 sensors "upstream" (on the manifold) and 2 "downstream" (one on each converter for the manifold).
Unplug the electrical wiring that connects to the O2 sensors. These are plug-style connectors. Squeeze the release tab and pull them off the sensor.
Unbolt the O2 sensor as you would any other bolt, but use an O2 sensor tool. Turn the O2 sensor counterclockwise to remove it.
Place a small dot of anti-seize compound on the new O2 sensors and install them. Installation is the reverse of removal.