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How to Replace an Oxygen Sensor on 2005 Subaru Outback

by Dan Ferrell

The oxygen sensor in your 2005 Subaru Outback measures the oxygen content in the gas stream going through the exhaust system. Your vehicle’s computer uses this and other sensors’ data to adjust the fuel injected into the combustion chambers. Hence, a bad sensor not only will send the wrong information to the computer but will have an impact on your Outback fuel consumption. Stop wasting fuel and restore engine performance by replacing this bad sensor in your own garage.

Removing the Old Oxygen Sensor

1

Start the engine and let it warm up for about 15 minutes or, if you prefer, run an errand and plan on replacing the oxygen sensor as soon as you are back home. Working on a warmed engine reduces the possibility of stripping the exhaust pipe threads as you remove the sensor.

2

Open the hood and disconnect the ground (black) battery cable with a wrench.

3

Take the air intake duct off the air intake assembly at the top of the engine with a flat-head screwdriver, if you have the 2.5L engine model. This will give you access to the oxygen sensor electrical connector.

4

Locate the oxygen sensor connected to the exhaust pipe. Follow the pipe attached to the exhaust manifold. The sensor has a cylindrical body, about the size of a spark plug and three wires coming out of the rear of the sensor that lead to an electrical connector.

5

Unplug the sensor’s electrical connector.

6

Lift the front of the Outback with a floor jack and support it with two jack stands.

7

Put on your goggles, crawl under the vehicle and remove the engine undercover with a ratchet, short ratchet extension and socket.

8

Put on your working gloves and unfasten the oxygen sensor form the exhaust pipe with a ratchet and an oxygen-sensor socket.

Installing the New Oxygen Sensor

1

Coat the threads of the new oxygen sensor with anti-seize compound, being careful not to get any compound on the tip of the sensor, and start the sensor into the exhaust pipe by hand.

2

Tighten the oxygen sensor with the ratchet and oxygen-sensor socket.

3

Reinstall the engine undercover with the ratchet, short ratchet extension and socket.

4

Lower your Outback off the jack stands.

5

Plug in the sensor’s electrical connector.

6

Replace the air intake duct with the flat-head screwdriver, if you have the 2.5L engine model.

7

Reconnect the ground (black) battery cable with the wrench.

Items you will need

References

About the Author

Since 2003 Dan Ferrell has contributed general and consumer-oriented news to television and the Web. His work has appeared in Texas, New Mexico and Miami and on various websites. Ferrell is a certified automation and control technician from the Advanced Technology Center in El Paso, Texas.

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