If the oxygen sensor is bad, it will not be able to tell when there's too much gas in the fuel mixture. this causes incomplete combustion which leads to less emission of co2 and nox pollutants, resulting in lower emissions than normal.
how does a bad oxygen sensor affect your car?
a bad oxygen sensor can lead to very expensive, difficult-to-diagnose problems.
a bad valve stem is an inexpensive part that rotates to either open or close the pulley wheel, spinning different fan speeds. a bad clogged fuel filter typically becomes evident in the form of spark plugs spitting white smoke when you start up your engine. is it worth paying a mechanic $60 for this relatively simple repair? it's recommended if you have lower amounts of gas in your tank, have cylinders missing when you turn on the engine, notice that your car “tops out” quickly when accelerating pedal is fully depressed, noticed low or no power when applying brakes at higher speeds or noticed spark plugs are spewing white smoke while starting the
can an o2 sensor cause a car to die?
yes.
a bad oxygen sensor can cause a car to die for many different reasons. the simplest of which is that it will likely be over leaned which can lead to any number of complications including increased fuel consumption or running rich. it could also trigger the service engine soon light by consuming extra fuel, cleaning the cat too much leading to possible catalytic failure, had an egr cooler go bad then recycle mode kicked in and commanded vacuum more often on injectors which are impossible to get power to at 190k engine speed after shutting down emission systems, or many other exotic reasons which are uncommon but exist.
a way around this problem is getting rid of excess heat from combustion gases before they get into the o2 sensor by installing a
how can you tell if an oxygen sensor is bad?
you can't.
there is no physical or chemical evidence that you can use to determine the integrity of an oxygen sensor, so it has to be replaced! there is a national institute for automotive service excellence (ase) certification test that checks that the replacement part matches the number and type on your service diagram (often called a pid), but this test isn't perfect and this process doesn't work with sensors. replacement sensors should come with a warranty, and you should replace them as soon as possible if they go bad.
will a bad o2 sensor cause power loss?
the 2 oxygen sensors traditionally used by car manufacturers are the upstream a2o2 sensor (sensitivity to lean, measures total air/fuel ratio) and downstream o2 sensor (sensitivity to rich). one of the most common misdiagnoses in engine diagnosis is seeing a malfunctioning downstream o2 sensor (rich) when it's actually the upstream a2o2 sensor that is malfunctioning. if this keeps occurring, then you will see power loss due to higher carbon monoxide levels internally.
typically these sensors are checked by an onboard monitoring system every few minutes, but if one of them malfunctions for some reason or input signal becomes abnormal, they may not be able to detect an issue until there's larger visible indications
