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What Size Is an Oxygen Sensor Socket? (Answered)

After being introduced in the 1980s, oxygen sensors brought about a revolution in the auto industry.

A faulty oxygen sensor should be removed immediately, but you may not have the right equipment. If you’re looking for the socket sizes, then you have landed on the right page!

What is an oxygen sensor socket?

Oxygen sensors are tiny socket-like shafts with a wire attached to them. The purpose of the oxygen sensor is to check the amount of oxygen present in the exhaust. Oxygen is necessary for the ignition of the car.

So, the oxygen sensor identifies the quality of fuel burning. It changes the ratio of oxygen to fuel as needed.

Now, this device can get damaged or nonfunctional with time. Due to their location and shape, it is hard to remove them with conventional instruments.

So, to replace the oxygen sensor, an oxygen sensor socket is required. This socket fits appropriately with the oxygen sensor. It makes the work easy for removing bad oxygen sensors.

The grippers in the sensor socket grip the oxygen sensor to prevent damage to both the sensor and wire.

The sophisticated oxygen sensors will get damaged if handled carelessly. The sockets make sure that your sensor does not get through abrasive practices.

What size is an oxygen sensor socket?

Oxygen sensor sockets mostly come in two sizes, the 3/8-inch drive and the 7/8-inch drive six-point sensor socket. The sockets weigh about 8 ounces. They are 5.75 inches long, 1.75 inches wide, and 2 inches tall. Other drive plug sets come in 5/8, ¾, and 13/16 inches.

The oxygen sensors do not vary by much in size. The standard sizes you will encounter are 22 millimeters or 7/8 inches drive. The sensor sockets properly fit the oxygen sensors, making it easy for you to open them.

One common thing that gets car owners confused is the oxygen sensor socket they need. It is sometimes labeled as a fraction of inches or millimeters.

The common measurements you will see are 7/8 inches and 22mm. While the values are not equal, they are close enough to be used interchangeably.

So, next time you see anyone suggesting a 22m, you can safely assume they are talking about 7/8 inch. 

Even though there are various car manufacturers out there, the sizes of their oxygen sensor sockets are pretty much the same. Let’s see which oxygen sensor sockets are required by different cars.


For a Honda, you would require a 7/8 oxygen sensor socket. The flexible 7/8-inch sensor wrench would work fine if you are looking for sockets. You can go for a 7/8” dual drive oxygen sensor socket.

Make sure you buy the 5-point sockets or wrenches.  


Like Honda, you need the same 7/8 inch or 22-millimeter wrench or sensor sockets. Make sure you buy 6 points one.


For an Audi, you will require a 21-millimeter oxygen sensor socket. Do not use 7/8 with them as it will rip the sensor.


Like most sensors, you can use a 22m or 7/8 inch sensor socket to open oxygen sensors from Denso cars.

Are all o2 sensors the same socket size? Are all O2 sensors 22mm?

So far, you may have heard that all the O2 sensors have the same socket size. But in reality, things are different.

The commonly labeled socket sizes are 22m and 7/8 inches. While inches are used in imperial measurements, millimeters are used in system international.

You will see people using these two measurements interchangeably. However, they are not equal. 7/8 inches is slightly bigger than 22 millimeters. So, when you use a 7/8 socket or wrench for a 22-millimeter oxygen sensor, there rises the risk of damage.

Not every O2 sensors are 22 millimeters. You will find plenty of 21 millimeters oxygen sensors. While different car manufactures have different preferences in their oxygen sensor size, the front and back sensors do not vary in size.

All the sensors are of the same size in a car. But car brand-wise, you will see a difference in oxygen sensor sizes.

Is a 7/8 socket the same as a 22mm oxygen sensor socket?

In short, the answer would be a 7/8-inch socket is the same as a 22-millimeter oxygen sensor socket. Many people would say that both the sockets are the same in size, but there is a subtle difference between them.

If you bring both into common terms, a 7/8 inches socket is slightly bigger than a 22-millimeter sensor socket. So, when the socket does not fit, the sensor may get damaged.

However, the difference is so subtle. You may not even realize it while working with your oxygen sensors. But you can never be too careful. One mishap and you will be stuck with the oxygen sensor, unable to open it by yourself.

Use a socket that correctly fits your oxygen sensor to save yourself from further hassles. And if you have no options left, you can use the sockets interchangeably.

How to remove the O2 sensor without a socket?

A lot of people think you need an oxygen sensor socket to get the oxygen sensor out, especially in Toyotas. However, you do not need a set of oxygen sensors in order to remove the oxygen socket from your car.

The steps are discussed below.

Identify nonfunctioning O2 sensor:

Get an OBD code scanner to identify O2 sensors. If you do not have a scanner, you may visit your local mechanic store.

Locate O2 sensor:

Some cars have multiple O2 sensors, which can go bad at the same time.

You will have to look for the sensor with a cable attached to it, trace the cable to get to the sensor. You will find the cable attached to the exhaust pipe. Disconnect the connector wire. 

Use penetrating spray:

You can use penetrating oils like WD40. The sensor is tightly fit, so you cannot open the sensor without penetrating oil. Properly apply oil around the sensor.

Get appropriate wrenches:

The trick is done by the standard 7/8 wrenches. Get another 13/16 wrench so you can apply pressure on it, or you can use a hammer. The 7/8 wrench is a must because it properly fits the O2 sensor.

Some would cut the wire plug for ease of work, but it is not necessary. You can easily slide through the wrench in. Once the 7/8 wrench is in place, apply pressure on it, and voila! Your O2 sensor will start to come off.

Final Thoughts 

Oxygen sensor sockets do not vary in size that much as the industry-standard oxygen sensors are only made in specific sizes which is 22mm. It is better to use appropriate tools dealing with oxygen sensors. However, you can settle for alternatives if the differences are not significant enough.