If your Toyota recently failed a state-required emissions test, a clogged oxygen sensor may be the problem. According to Sierra Research, Inc., faulty oxygen sensors are the greatest contributors to excessive emissions in cars with fuel-injected engines. To get your Toyota back to legal emission status, simply buy a new one. If you're strapped for cash, however, you might be able to save some money by cleaning your sensor.
Take the oxygen sensor out of your Toyota engine. The "Resources" section below offers a link to step-by-step directions on how to do this.
Once you have removed the oxygen sensor, look it over. If the sensor looks normal (no cut wires, cracks or other evidence of damage), then clogs from dirt and debris are likely the cause of the problem. In such cases, cleaning the sensor may restore it to legal effectiveness.
Put the oxygen sensor into the gas-safe container. Fill the container with gas so that the sensor is completely submerged.
Tightly cap the container. This will prevent the gasoline from evaporating during the cleaning process.
Gently rotate the container so that the gasoline swirls into and out of the oxygen sensor. Let the container sit in a safe place for 10 to 12 hours.
Return to the container and rotate it again. This dislodges the corroded material that was loosened by the gasoline.
Use rubber gloves to extract the Toyota oxygen sensor from the gasoline bath. Dry the sensor with an old cloth or paper towels. Return the cleaned sensor to its proper place in your engine, and take your Toyota to be reinspected.
Dispose of the gasoline. The gas you used probably is full of corroded materials, so don't simply dump it into your fuel tank. To properly dispose of the gasoline, take it to your local hazardous waste disposal centre. The "government" section of your phone book should list the locations of these facilities.
Never dispose of gasoline by pouring it down the drain or placing it in the trash. Such means of disposal are hazardous to the environment and could result in a fine.