How to Change the Oxygen Sensor on a Chevy Cavalierby Jody L. Campbell
The common engine in the Chevy Cavalier is the 2.2 liter four cylinder. A few models have a 2.4 liter engine. Both engines use two oxygen sensors. Oxygen sensors read the amount of air and burned fuels in the exhaust system and transmit that data to the engine management computer through voltage. The computer then adjusts the ratio of air and fuel to lower the pollution in exhaust. When the sensor fails in the Cavalier, the computer ignores it and makes its own adjustments, which can cause more pollution, less gas mileage or both.
Locate the oxygen sensor that needs replacing. If you're replacing the front one (upstream), you can access it in the engine compartment by lifting the hood. If you are replacing the rear sensor (downstream), you'll need to lift the Cavalier's front end with the floor jack and support it safely and securely onto the jack stands. The front sensor is located in the front lower center of the engine and screwed into the header pipe. The rear sensor is located in the exhaust pipe near the catalytic converter. Put on safety glasses if you crawl under the Cavalier.
Locate the wire harness to the oxygen sensor. Use the flathead screwdriver to press in on the clip lock of the plug on the oxygen sensor wire and separate it from the wire harness.
Spray a liberal amount of penetrating oil on the threads of the oxygen sensor and allow the oil to soak in.
Place the box end wrench or socket onto the oxygen sensor and turn it counterclockwise to unthread it from the exhaust pipe. Remove the sensor.
Thread the new sensor into the oxygen sensor porthole in the exhaust pipe and tighten using the wrench or socket and a ratchet. Do not overtighten. Make sure its snug, but it is easy to strip the threads on the oxygen sensor so be careful.
Plug the oxygen sensor wire back into the wire harness and secure the wire so it does not dangle.
Remove the tools and either lower the vehicle or close the hood.
- Only use a direct-fit oxygen sensor replacement. Although little more expensive in some applications, they are well worth the investment. The universal sensors have to be wired in, and the colors of the wires do not always match the color of the wire harness wires. The direct-fit sensor comes with a plug that will have the correct wires and directly plug into the wire harness. To reset the check engine light (activated by the failed sensor), disconnect the negative battery terminal for five minutes and then replace.
- Never attempt to replace an oxygen sensor in the Chevy Cavalier when the motor is hot.