How to Fix your Car's Oxygen Sensor

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What fresh Horror is this?
When the infamous "Check Engine light" comes on the very sight of it can cause dismay, a furrowed brow, and a knot in the stomach. Nobody wants to deal with a check engine light. Yet there it is, glowing amber for all the world to see. Fortunately, the vast majority of the time, that little engine icon means that your motor is either running too rich or running too lean thanks to a faulty oxygen sensor. In fact, a malfunctioning oxygen sensor is the number one reason why check engine lights come on in motor vehicles in the United States, right at the top of the list behind a loose gas cap or that your catalytic converter is failing.
 
If you own a new car that is still under warranty and you have a defective o2 sensor, it is covered under the automaker's warranty. Oxygen sensors can last for up to 100,000 miles on today's vehicles. But if you have an older car, sensors can malfunction after about 50,000 miles and need to be replaced. If you don't replace a faulty oxygen sensor it can cause the engine to run unbalanced, creating chemical deposits and failure of your catalytic converter. Replacing the oxygen sensor only costs a few hundred dollars at a shop where replacing a catalytic converter can run up to $2,500! It pays to replace that sensor.
How do you fix your car's oxygen sensor?
Luckily, it's not that difficult. The first step is to diagnose the cause of that amber light being on and that means you'll need a OBD 2 reader. OBD stands for onboard diagnostics and this electronic tool is a diagnostic scanner that reads your car's fault codes and memory errors.
Basically, an OBD reader allows you to establish a connection between your car and a mobile app or diagnostic software. Once the connection is established, if you are using a mobile app, you can easily access your car's data from your smartphone. These can be purchased for as little as $60 on Amazon. If you don't own an OBD 2 reader, you can bring your car to any Lithia Auto dealership, and we'll diagnose the reason why your check engine light is on quick and easy.
 
If the fault code reads PO134 that means that your vehicle's o2 sensor (bank one, sensor one) is malfunctioning. The engine control module detects that the oxygen sensor is at a standstill and is not reading the amount of oxygen in the exhaust. However, there are other problems such as a disconnected vacuum hose, that can trigger the same code reading.
Many times, your car will seem to be running fine but because the oxygen sensor is not doing its job, your car is actually using much more gasoline, reducing as much as 40 percent of your fuel economy. With the cost of gas today, that's not good. Besides fuel consumption, the oxygen sensor monitors the emissions coming out of your exhaust system so a malfunctioning oxygen sensor can mean your car is polluting more than it should and that's not good for any of us, or the planet.
 
Today's cars can have as many as four oxygen sensors, so it is important to be able to diagnose which one is faulty. The sensor itself is about the size of a spark plug and just unscrews, so replacing it is easy, though some of these sensors are in hard-to-reach places. Plus, the extreme heat of your exhaust system can cause your old sensor to seize in place, making it extremely difficult to unscrew.

What does an Oxygen Sensor Do?

As mentioned earlier, some vehicles have more than one oxygen sensor, but they all live somewhere in the exhaust system and are unique in that they generate voltage using a heat-induced chemical reaction.
 
The purpose of these sensors is to measure the oxygen levels between the outside air and what is represented in the exhaust gas. The sensor sends a signal to your car's computer which monitors whether exhaust gasses are exhibiting too much fuel to air ratio, causing the engine to run rich, or too little fuel to air ratio, causing it to run too lean. That is why a malfunctioning sensor can cause poor fuel economy or an unhealthy level of emissions and air pollutants.
 
In either event, a bad sensor will cause the engine to run unbalanced, creating stress on engine components, and if you continue to run your car with a failed sensor, it can cause engine damage.
The Fix
If you decide to replace the oxygen sensor yourself, the actual part will cost less than $200. Running an OBD 2 scan will tell you if you have a faulty sensor. Once you locate the sensor it is just a matter of unscrewing the old one, unplugging it, and replacing it with the new one. Make sure there is no grease on the new sensor because it will affect a proper reading.
 
Let Lithia Help!
If you don't own an OBD 2 scanner diagnostic tool or if the sensor is difficult to reach, it may be easier to trust the ASE trained service professionals at the Lithia Auto dealer near you.