How to Check the Ohms on Your Oxygen Sensor

A red car in a showroom.
What You'll Need
Multimeter
Gloves
Pencil
Paper
What You'll Need
Multimeter
Gloves
Pencil
Paper

It is important to know how to check the ohms in your oxygen sensor. Understanding what ohms are is a good start to knowing how to check them on your oxygen sensor. Ohms are basically the resistance that goes on between two points of a specific conductor. This takes place whenever there is a potential difference of a single volt that is constantly applied to each of the two points. Typically, ohms measures a resistance in the conductor that is nearly constant with a specific type of parameters, temperatures, and other voltages.

It is important to know how to check the ohms in your oxygen sensor. Understanding what exactly ohms are is a good start to understanding how to check them on your oxygen sensor. Ohms are basically the resistance that goes on between 2 points of a specific conductor. This takes place whenever there is potential difference of a single volt that is constantly applied to each of the 2 points. This will in turn causes the conductor to make a current that is just 1 ampere. There will not be any type of electromotive force with the conductor. Typically, ohms have a resistance in the conductor that is nearly constant with a specific type of parameters, temperatures and other voltages.
Materials Needed:
Multi Meter
Gloves
Pencil
Paper
Step 1 – Turn off Engine
The first and most important thing that you should do is make sure that the engine to your vehicle is turned off. It is a good idea to have had your vehicle turned off for at least thirty minutes to an hour. This will give your vehicle sufficient time to cool off so that you will be able to work without getting burned. Set your car in the shade if it is especially hot and sunny out, this will help your car to cool off much quicker.
Step 2 – Separate Connector
It is a good idea to still use gloves, even after your car has been given time to cool off. This will help prevent you from injury. However, you should make sure that you can move your hands around in the gloves with no constrictions. The connector for the oxygen sensor needs to first be separated before you can do anything. There should be latch tabs that are on either side that need to be pushed in so that it can be pulled apart.
Step 3 – Identify
Once the two pieces have been pulled apart, look at each one closely so that they can be identified. The side of the connector that has pins is the actual sensor. The other side will have holes where the wires can be inserted. This is the side that is wired to your ECU. Look to the sensor side of the connector. There should be 4 pins. The first two are the pins that are wired to the heating element. The other 2 pins are the pins that are used for the signal of the oxygen sensor.
Step 4 – Multi Meter
You will need to get your multi meter to read in a resistance in ohms. Once you have done this, you will need to connect it to the pins for the oxygen sensor. While you are there, it is also a good idea to check the pins for the heating element as well. Make sure that you know what a good reading is and what a bad reading is whenever you are doing this. It is a good idea to write it down along with what the ideal reading should be.

Step 1 - Turn off Engine

The first and most important thing that you should do is make sure that the engine to your vehicle is turned off. It is a good idea to have had your vehicle turned off for at least thirty minutes to an hour. This will give your vehicle sufficient time to cool off so that you will be able to work without getting burned. Set your car in the shade if it is especially hot and sunny out. This will help your car cool off much quicker.

Step 2 - Separate Connector

It is a good idea to still use gloves, even after your car has been given time to cool. This will help prevent injury. However, you should make sure that you can move your hands around in the gloves with no constrictions. The connector for the oxygen sensor needs to first be separated before you can do anything. There should be latch tabs that are on either side that need to be pushed in so that it can be pulled apart.

Step 3 - Identify

Once the two pieces have been pulled apart, look at each one closely so that they can be identified. The side of the connector that has pins is the actual sensor. The other side will have holes where the wires can be inserted. This is the side that is wired to your ECU. Look to the sensor side of the connector. There should be four pins. The first two are the pins that are wired to the heating element. The other two pins are the pins that are used for the signal of the oxygen sensor.

Step 4 - Use a Multimeter

You will need to get your multi meter to read resistance in ohms. Once you have done this, you will need to connect it to the pins for the oxygen sensor. While you are there, it is also a good idea to check the pins for the heating element as well. Make sure that you know the difference between a good reading and a bad reading whenever you are doing this. It is a good idea to write it down along with what the ideal reading should be.