Your BMW 525i oxygen sensor works under some pretty strenuous conditions. Located near the exhaust manifold, the 525i oxygen sensor analyzes the oxygen content of the hot exhaust gases leaving your cylinders, and sends this information to your car's computer hundreds of times per minute. Your car uses the information obtained from the BMW 525i oxygen sensor to regulate the amount of fuel injected into the combustion chambers.

When your 525i oxygen sensor is not working properly, your car has to rely on other sensors in the network to guess at the oxygen content of your exhaust. Since the BMW 525i oxygen sensor is the only sensor near the exhaust manifold, other measurements are not as accurate as they should be.

What does this mean for your engine's performance? A faulty 525i oxygen sensor typically means that your car is using more fuel than it needs for optimal performance. In other words, a bad BMW 525i oxygen sensor wastes gas—which is expensive enough in the first place. It is not always easy to tell when your 525i oxygen sensor is not working. Other than a decrease in fuel economy, which can be attributed to other engine problems, symptoms of a faulty BMW 525i oxygen sensor include poor idling, black exhaust smoke, and a rotten-egg odor from your exhaust. Sometimes a diagnostics test can detect a bad 525i oxygen sensor, but even this test is not always reliable. When your BMW 525i oxygen sensor is on the way out, it may work sporadically rather than quit altogether, which means a diagnostics test is not a foolproof method. If your car fails an emissions test, your failing 525i oxygen sensor may be to blame.You don't have to take chances with your fuel economy and engine performance when you order a new BMW 525i oxygen sensor from our extensive online catalogue.