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Home >   How To >   Buyer's Guides >   Oxygen Sensor Buyer's Guide

Oxygen Sensor Buyer's Guide

 

 

How to Buy an Oxygen Sensor


 

How to Buy an Oxygen Sensor

Automobiles include a number of sensors such as the oxygen sensor,  
air-fuel ratio sensor, parking sensor and tire pressure monitor sensor  
(TPMS)
. Each sensor is meant for a specific purpose that helps the  
vehicle run at optimal efficiency. The oxygen sensor is one of the  
important sensors that checks the air-fuel ratio and exhaust emissions.  
This buyer's guide provides you the basic details, location and  
functionality of the oxygen sensor. We make it easy at BuyAutoParts.com to find the right oxygen sensor replacement for your automobile.

 

Function of an Oxygen Sensor

 

The oxygen (O2) sensor senses the amount of oxygen in the vehicle's exhaust. It is usually located in the exhaust pipe. The oxygen sensor reading is used by the Engine Control Unit (ECU) to regulate the amount of air and fuel sent to the engine. The oxygen sensor mainly serves two purposes: It helps maintain the perfect air-fuel ratio, thereby preventing the engine from running lean/rich; it also reduces the exhaust emissions. One end of the oxygen sensor detects the amount of oxygen while the other end connects to the wiring that relays the sensor's reading to the ECU.

 


Oxygen Sensor
 

 

Heated and Non-heated Oxygen Sensors

 

Oxygen sensors need an optimal temperature of 650?? Fahrenheit to function effectively. Non-heated sensors, which were used in older automobiles, were heated by the exhaust gases. The disadvantage of these sensors were that it could take a minute or longer to reach the temperature required for operation. Non-heated sensors overcame this problem through a heating element, a resistor, which heats the sensor to the required temperature for operation.

 

 

Narrowband and Wideband Oxygen Sensors

 

Narrowband oxygen sensors inform the ECU whether the engine is running lean/rich with reference to the stoichoimetric air/fuel ratio (14.7:1). Wideband oxygen sensors, commonly referred to as air-fuel ratio sensors, tell the ECU how rich or lean the engine is running in comparison with the stoichoimetric ratio. Wideband oxygen sensors are commonly used in newer automobiles.

 

Find a more detailed explanation on the difference between oxygen sensors and air-fuel ratio sensors in this link: Oxygen or Air Fuel Ratio Sensor

 

 

Upstream and Downstream Sensors

 

The upstream oxygen sensor is situated before the catalytic converter whereas the downstream oxygen sensor is located after the catalytic converter. The upstream sensor monitors the level of pollutants in the engine's exhaust and sends this information to the ECU that continuously adjusts the air-fuel ratio. The downstream sensor measures the level of pollutants passing through the catalytic converter. The information from the upstream and downstream sensors are compared by the ECU. If the readings from the two sensors become more similar to each other, the ECU triggers a catalyst inefficiency code.

 

 

Location

 

Knowing the location of the oxygen sensor at fault is important. The number and location of the oxygen sensors are specific to every vehicle's year, make and model. The location of the oxygen sensor is usually identified by position (sensor 1, sensor 2) and by cylinder bank (bank 1, bank 2).

 

Bank 1 is the side of the engine where cylinder #1 is located.

Bank 2 is opposite to Bank 1.

Sensor 1 is the upstream sensor.

Sensor 2 is the downstream sensor.

 

In case of a four-cylinder engine, there is only one bank: bank 1.

 

The following link depicts the various locations of oxygen sensors:Location of the Oxygen Sensor and Its bank

 

 

Problems

 

An oxygen sensor may get damaged due to normal wear and tear. However, over time, carbon deposits may build up over the sensors, preventing them from functioning properly. The sensor can also get contaminated with silicon content from the coolant or anti-freeze.

 

 

Symptoms

 

When the oxygen sensor starts to fail, it exhibits a few symptoms. Some of them are as follows:

 

Rough Engine Idle

 

A bad oxygen sensor will send incorrect information to the ECU. This may result in the injection of more fuel to the engine than required, causing the engine to stall. This, in turn, induces the engine to experience a rough idle.

 

Increased Emissions

 

A defective oxygen sensor will fail to keep the exhaust emissions under check, thereby resulting in increased exhaust emissions. Increased emissions are due to the engine running rich/lean.

 

Poor Gas Mileage

 

An automobile's gas mileage is disrupted by a malfunctioning oxygen sensor. The bad sensor will make the ECU deliver an improper amount of fuel to the engine resulting in decreased gas mileage.

 

Engine Misfiring

 

When the amount of air-fuel mixture sent to the engine is not optimal, the combustion in the engine cylinders get affected, which can cause the engine to misfire. This usually occurs either when the engine accelerates or idles. Engine hesitation, which occurs during acceleration, is also an indicator of a bad oxygen sensor.

 

Maintenance

 

Having your oxygen sensor regularly cleaned for impurities can ensure their proper function. Some cars have a special O2 sensor light on their dashboard that indicates when to check the oxygen sensor. Unheated sensors usually last 30,000 to 50,000 miles, while newer oxygen sensors need to be replaced at about 100,000 miles. This information is usually provided in the vehicle's manual. Learn more about oxygen sensor's life expectancy in this link: Oxygen Sensor Life Expectancy

 

Direct-Fit or Universal-Fit

 

Direct-Fit Oxygen Sensor

 

The name of this style is pretty self-explanatory. These oxygen sensors are designed to precisely bolt onto your application without any additional modifications.

 

Universal-Fit Oxygen Sensor

 

The alternative to a direct-fit style is the universal-fit oxygen sensor which does require some minor modifications. This style fits hundreds of applications but you still need to confirm your application before purchasing. This style is recommended if your vehicle already has a universal-fit oxygen sensor in it or if you are looking for a more cost-effective option.

 

Oxygen Sensor Kit

 

BuyAutoParts.com carries a wide range of oxygen sensor kits for every make and model. Getting an oxygen sensor kit will give you a large discount. We also stock air-fuel ratio sensors and other sensors.

 

Oxygen Sensor Kit

Finding Your Oxygen Sensor's OEM Part Number

 

If for any reason you cannot find your oxygen sensor by entering your vehicle's year, make and model, you can find it by its Original Equipment Manufacturer (OEM) number. The OEM part number can be found directly on the part itself. You can also call a dealership with your VIN, and they will provide you with the OEM part number. You can give one of our car specialists a call at 1-888-907-7225 for further assistance in purchasing your oxygen sensor.

 

Part Numbers On an Oxygen Sensor

 

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Frequently Asked Questions

 

How many oxygen sensors does my vehicle have?

This depends on your automobile's year, make and model. Older automobiles had a minimum of two sensors whereas newer automobiles can have six, eight or more oxygen sensors.

 

 

What is California emissions sensor?

This sensor is designed specially to meet the emissions specifications for the State of California. You can get California emissions compliant sensors for your vehicle at BuyAutoParts.com.

 

 

My oxygen sensor has an orange/black/white color. What does it mean?

An orange-colored oxygen sensor is usually an indication of lead poisoning. The oxygen sensor might also turn black indicating carbon buildup or may turn white due to silicone poisoning or antifreeze contamination. The source of these problems should be inspected and fixed, before replacing the oxygen sensors.

 

 

What do the P0130 and P0136 codes mean?

The P0130 code indicates the malfunctioning of the oxygen sensor (Bank 1, Sensor 1) and P0136 code indicates defective oxygen sensor (Bank 2, Sensor 1).

 

 

 

Find more FAQ regarding oxygen sensors in this link: How Much Does an Oxygen Sensor Cost?

 

 

Installation Video

 

Oxygen Sensor Replacement

 




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