Oxygen Sensor Buyer's Guide
- Oxygen sensors work by monitoring the amount of oxygen in the exhaust pipe. An oxygen sensor sends a signal to the Engine Control Unit (ECU) to adjust the amount of fuel injected in the combustion chambers.
- The three most common types of oxygen sensors are the Zirconia 02 sensor, Titania 02 sensor, and Wide Band 02 sensor.
- Faulty oxygen sensor signs include rotten egg smell from exhaust pipes, irregular engine idling, and poor gas mileage.
- It is important to have a faulty oxygen sensor replaced because not only does it cause harm to the environment, but it’s also vital to your vehicle’s overall performance.
Car pollutants cause long-term damage to the environment. However, car owners can reduce the amount of harmful substances emitted by their car’s exhaust system with the help of an oxygen sensor. Apart from helping the environment, oxygen sensors also play a role in keeping your car engine’s health at its best.
What is an oxygen sensor and how does it work?
The wrong mixture of oxygen and gasoline can do more damage to the environment than it already does. Oxygen sensors work by monitoring the amount of oxygen in the exhaust pipe. Too much or too little oxygen is not good for the engine’s health. The oxygen sensor helps create a balance by sending a signal to the Engine Control Unit (ECU) to adjust the amount of fuel injected into the combustion chambers.
Oxygen sensors can either be installed in the front or rear of the car. A front oxygen sensor is installed at the front exhaust pipe near the catalytic converter or at the exhaust manifold. It is responsible for keeping the air-fuel ratio at an ideal level. In some cars, an air-fuel ratio sensor is sometimes used instead of a front oxygen sensor.
A rear oxygen sensor is mounted right after the catalytic converter. It is usually mounted in the exhaust itself. The rear oxygen sensor is usually used to monitor the performance of the catalytic converters.
Volvo was the first to use oxygen sensors in the1970s. The first oxygen sensors were made from Zirconia, with only one or two wires on it. Older vehicles were only equipped with one oxygen sensor. Every automobile manufactured after the 1980s is equipped with an oxygen sensor.
Over the years, the demand for oxygen sensors has changed. Today’s vehicles can have up to eight oxygen sensors, depending on capacity. Cars with 4-cylinder engines usually have two oxygen sensors installed, while other vehicles with V6 and V8 must have at least four oxygen sensors installed.
What are the types of oxygen sensors?
There plenty of oxygen sensors available today. These can be classified into three types: Zirconia O2 sensors, Titania O2 sensors, and Wide Band O2 sensors.
Zirconia Oxygen Sensors
Zirconia oxygen sensors are the most common type of O2 sensors. This type of oxygen sensor can further be classified into unheated and heated zirconia oxygen sensors.
Unheated oxygen sensors rely on heat to send signals to the ECU. One drawback is that it takes a lot of time for the exhaust to heat up and the signal may not be sent the signal at the right time. This may confuse the ECU, causing it to go back to its default setting and releasing the wrong amount of fuel to the combustion chambers.
Heated oxygen sensors are more advanced because it has a heater circuit installed. This automatically heats up the sensor when starting the car, making it more efficient than unheated oxygen sensors. A heated oxygen sensor also decreases the possibility of error by sending timely, accurate signals to the ECU.
Titania Oxygen Sensors
What makes this type unique is that it is made of a ceramic material rather than the usual zirconia. It also uses a different process in sending signals to the ECU. Titania oxygen sensors are usually found in limited edition vehicles only.
Wide-Band Oxygen Sensors
This is a new type of oxygen sensor which is not yet widely used. This type of sensor creates a higher level of voltage than a zirconia oxygen sensor, making it more efficient in balancing the air-fuel ratio in the engine’s exhaust pipes.
When is the right time to replace an oxygen sensor?
It is important to have a faulty oxygen sensor replaced because not only does it cause harm to the environment, it is also vital to your vehicle’s overall performance.
A car’s engine should be checked as soon as the “check engine light” illuminates. If you notice an unusual smell, similar to rotten eggs, coming from your engine’s exhaust; it is time to contact your trusted mechanic. There is a high probability that something is wrong with your engine’s oxygen sensor. Other signs to look out for are irregular engine idling and poor gas mileage.
What to consider when buying an oxygen sensor?
An OEM replacement oxygen sensor is usually priced at $20 to $100. Take note that O2 sensor prices will really depend on the model and make of your car. Some are priced more than the estimates. Aftermarket oxygen sensors are also available.
An oxygen sensor is usually sold individually. They come in 1-wire, 2-wire, 3-wire and 4-wire variants.
Which oxygen sensor should you buy?
There are a lot of questions about which oxygen sensor to replace. In fact, failures are common among cars especially when the wrong sensor is installed. With today's automobiles equipped with at least two, or even three or four oxygen sensors, it can be very confusing as to which one is not working correctly. There are probably a lot of sensor codes to choose from and here's a tip to help you sense the right oxygen sensor.
Oxygen sensors are always numbered this way:
- Bank 1 Sensor 1
- Bank 2 Sensor 1
- Bank 1 Sensor 2
- Bank 2 Sensor 2
Other manufacturers code their oxygen sensors this way, which is why it can sometimes be very confusing. However, they all mean the same:
- Sensor 1/1 or O2s 1/1
- Sensor 2/1 or O2s 2/1
- Sensor 1/2 or O2s 1/2
- Sensor 2/2 or O2s 2/2
Now here's a detailed list to know which is which:
- Bank 1 is located at the side of the engine where cylinder #1 is found as well.
- Bank 2 is on the opposite side of Bank 1.
- On a 4-cylinder engine, there is only one bank that's called Bank 1.
- Sensor 1 is the upstream sensor located before the catalytic converter.
- Sensor 2 is the downstream sensor located after the catalytic converter.
- Sensor 3 is the only downstream sensor in situations where there are two sensors before the catalytic converter and only one after it. On other cars, this is read as Bank 1 Sensor 3.
With these detailed tips on how to sense the right oxygen sensor, you'd be sure to buy the right replacement part at your store. Be sure to purchase one from a trusted brand to avoid any complications you might experience with ones that are bought from local junkyards. Enjoy your shopping!
Oxygen Sensor Maintenance
Oxygen sensors are these tiny devices inside the car that basically balance the fuel to oxygen ratio. It is important to keep this in top shape at all times since it helps in controlling the emissions of the vehicle. If you're an experienced DIYer, then you're at an advantage here. Repairing these auto parts yourself are better than taking it to the mechanic and end up being buried in expensive fees. However, if you do it yourself, you get to save up and do it at your most convenient time. All you need are tools and a garage to work in and you can repair your worn-out oxygen sensor in no time!
What you need:
- Jack stand
- Wire brush
- Spray air
- Socket set
- Plastic container
Step 1: Find out which sensor needs to be repaired. It's a good idea to take it to an auto shop to run a free diagnostic test to find out which sensor needs to be fixed.
Step 2: Using the jack, jack up your car and set the jack stands in place. Then, find the damaged oxygen sensor and take it out. Remove it by unbolting the retaining bolts using a socket set and unplug it from the electric wiring harness.
Step 3: Slowly but thoroughly, scrub the metal tube-shaped end of the sensor using a wire brush. To clean it more, get the compressed air and spray it.
Step 4: Get the plastic container and fill it with gasoline. Get the metal tube-shaped half of the oxygen sensor and let it sit in the gasoline-filled container over night.
Step 5: The next day, remove it and towel it dry. Reinstall the sensor back in place by placing the retaining bolts back in using the socket set. Then, plug the electric wiring back in.
After doing all these steps, you're sure to get your oxygen sensor clean. This should even let you travel the miles before having to completely replace it. With just a few tools, you can get your oxygen sensor repaired easily in no time at all!