Fuel and air are two of the four ingredients that help your car make power. Your engine needs them both in just the right amount to run efficiently, and the job of determining the mixture falls upon your Audi oxygen sensor. The Audi oxygen sensor is a neat little device that sniffs the exhaust as it passes by. By detecting the remaining oxygen in the exhaust, the Audi oxygen sensor then tells your vehicle's computer whether to richen the mixture or lean it out to end up with the right proportions. But your Audi oxygen sensor does more than just keep your fuel economy and power as high as possible. The Audi oxygen sensor also protects your catalytic converter by ensuring that enough oxygen remains in the exhaust for the catalyst to do its job. Frequently, when you get a bad Audi oxygen sensor, it can lead to a bad Audi catalytic converter too. So if you get a "check engine" light on your car, don't just ignore it. It might be your Audi O2 sensor telling you there's a problem, and the problem can get bigger if you ignore your Audi oxygen sensor. If you were worried about the cost of a new Audi oxygen sensor, don't be. We have the Audi oxygen sensor to fit your car available for a fraction of the price other parts places will charge. Low prices and fast shipping: We're making Audi oxygen sensor replacement as painless as possible.