Your 2000 Toyota Corolla's oxygen sensor gathers information about the exhaust coming out of the engine. It then sends this information to the Corolla's computer, called an electronic control unit. This electronic control unit, or ECU, adjusts the air to fuel ratio so that the engine optimizes fuel economy and horsepower. Over time, these oxygen sensors will fail. Replacement sensors can be purchased from most auto parts stores.
Jack up the front of the Corolla using a floor jack underneath the front jack point of the Corolla just behind the radiator support.
Place a jack stand under each of the front pinch welds on the body of the vehicle under the front doors.
Lower the Corolla onto the jack stands.
Climb under the vehicle and locate the two oxygen sensors. One sensor will be in front of the catalytic converter towards the front of the vehicle. The other oxygen sensor will be behind the catalytic converter towards the middle of the vehicle. The sensors will look like plugs sticking out of the exhaust with wires coming out of the sensors.
Disconnect the electrical leads from the oxygen sensors by pushing down on the release tab on the sensor connector and pulling it off of the sensor.
Unbolt the sensors from the exhaust using a socket wrench and O2 sensor socket.
Thread and tighten the new sensors using an O2 sensor socket and socket wrench.
Reconnect the electrical connectors to the sensors.
Lower the Corolla to the ground using the floor jack.
