Your BMW 740i oxygen sensor is located near your exhaust manifold. The job of your 740i oxygen sensor is simple and repetitive, but crucial to the performance of your combustion system. The BMW 740i oxygen sensor, also referred to as an O2 sensor, is responsible for measuring the amount of oxygen that is present in the exhaust gas leaving your combustion cylinders.

Your car's computer relies on your 740i oxygen sensor to send accurate measurements of the oxygen content, so that it can determine the amount of fuel that should be injected into your cylinders. The hard-working BMW 740i oxygen sensor measures your hot exhaust hundreds of times each minute and transmits this information to your computer.

A faulty 740i oxygen sensor cannot take these measurements, and your car is forced to rely on other sensors in the network to estimate the amount of oxygen in your exhaust. Since the other sensors are not located near the actual exhaust stream, the measurements obtained when your BMW 740i oxygen sensor is bad are not reliable. Typically, this means that your car will send too much fuel into your cylinders rather than too little. You can easily see that a faulty 740i oxygen sensor causes a drop in fuel efficiency, and with today's high gas prices you cannot afford to waste fuel. Diagnosing a bad BMW 740i oxygen sensor is sometimes tricky, as your 740i oxygen sensor may work intermittently and a diagnostics check will not always catch malfunction. If your car fails an emissions test, it may be due to a faulty BMW 740i oxygen sensor.Your best bet is to replace your 740i oxygen sensor with a quality replacement sensor from our online catalogue.