How to Check Catalytic Converter With Scan Tool

Whether it’s an engine misfire, a noticeable decrease in fuel efficiency, or signs of excessive emissions, there are many issues that can arise from a malfunctioning catalytic converter. 

How to Check Catalytic Converter With Scan Tool

If you suspect that your car’s catalytic converter may have gone bad and wish to diagnose the issue without having to take it to a mechanic right away, then being able to check your catalytic converter with a scan tool is an excellent way of tackling the problem yourself.

In this blog post on how to check catalytic converter with scan tool, we will examine exactly how to go about checking and diagnosing your cat using a scan tool so that you can get back on the road as quickly as possible!

What is Catalytic Converter?

The catalytic converter is an emissions control device that converts toxic exhaust substances produced by the engine into less harmful gases before they are released out of the tailpipe. It is an essential part of a vehicle’s emission system, ensuring that your car runs smoothly and efficiently while also reducing unhealthy fumes from being released into the atmosphere.

11 Step-by-step Guidelines on How to Check Catalytic Converter With Scan Tool:

Step 1: Gather the Necessary Tools and Equipment

To begin, you will need a few basic tools and equipment including a handheld scan tool, a multi-meter, and a stiff wire brush. It is also helpful to have an assistant for this process. But don’t worry, it’s an easy process that can be done alone as well! It is also recommended that you wear appropriate safety gear such as gloves and safety glasses for additional protection.

But most importantly, make sure that the engine is off and cooled down before you begin.

Step 2: Connect the Scan Tool to Your Car’s Computer

Next, you will need to connect the scan tool to your car’s onboard computer. This is typically done by plugging one end of the tool into the diagnostic port located underneath the dashboard on the passenger side.

This port should be clearly marked and labeled as a “Diagnostic Port.” It is also useful to consult the car’s manual for exact instructions on how to connect and operate the scan tool. It is important to remember that the scan tool should be disconnected when not in use.

Step 3: Access The Diagnostic Menu On Your Scan Tool

Once plugged in, access the diagnostics menu by turning on your scan tool and following its instructions accordingly.

Access the Diagnostics Menu by Turning on

But before you continue onto the next step, it is important to note that some scan tools may require you to select the “Catalytic Converter” option from the menu – or select a specific code for that device. It is useful to refer to the car’s manual for exact instructions on how to do this. If your scan tool does not have this option, you can simply select the “Diagnostic” menu to continue.

Step 4: Retrieve Any Error Codes That Are Present

The next step is to check for any error codes that may be present. If there are any fault codes related to the catalytic converter, they should be displayed on the scan tool’s display screen.

If no codes are present, try disconnecting the battery for a few minutes to reset any error codes that may have been stored in your car’s computer system. If the codes still do not appear, then your catalytic converter is likely not the source of the issue.

Step 5: Inspect Your Catalytic Converter

If there are codes present, you can now move on to the physical inspection of your catalytic converter. To do this, open up your hood and take off the heat shields or other obstructions that may be covering it.

Use a stiff wire brush to scrub away any debris or dirt from around the exterior of the catalytic converter. But be careful not to touch any of the internal parts or wiring. It is also a good idea to check for any physical signs of damage such as cracks, rust, or corrosion.

Step 6: Look For Any Obvious Damage

Replace Your Catalytic Converter

Now look closely for any signs of damage or corrosion. If you see any, then it may be time to replace your catalytic converter. It is important to note that physical signs of damage may not always be obvious, so if you have reached this step and are still having issues, then the next step may be to perform a full diagnostic scan. This can be done with the assistance of a qualified mechanic if necessary.

It is also possible to perform this step yourself with the proper tools and equipment.

Step 7: Check The Temperature of the Catalytic Converter

Using a multimeter, check the temperature of the catalytic converter to make sure it is within normal operating temperatures. This should be done when the engine is running as it will give you an indication of how well your cat is functioning and whether or not it needs to be replaced.

But be sure to wear gloves and safety glasses for protection while doing this. If the temperature is too high, then it may be time to replace your catalytic converter. This is best done by a qualified mechanic.

Step 8: Inspect The Oxygen Sensors

It’s also important to inspect your oxygen sensors for any damage as this can cause issues with how efficiently your car’s engine runs. Start by checking the connection between each sensor and its wiring harness, making sure everything is correctly connected. This should be done with the engine off to prevent any damage. If everything looks good, then you can move on to the next step.

However, if you notice any damage or corrosion then it may be time to replace the oxygen sensors.

Step 9: Test the Oxygen Sensors

This Can Be Done With a Multimeter

Now it’s time to test the oxygen sensors themselves. This can be done with a multi-meter by taking readings from each of the four exhaust pipes. If there are any inconsistencies in these readings then this could indicate an issue with your catalytic converter. If this is the case, then it’s time to replace it.

Otherwise, you can move on to the next step. Make sure to take note of any readings before moving on.

Step 10: Check for Blocked Exhaust Pipes

Your final step is to check for any blocked or restricted exhaust pipes. This can be done by using a pressure gauge, which will help to diagnose whether or not your cat has become clogged and needs replacing.

It is also a good idea to inspect the exhaust system for any signs of physical damage or corrosion as this could potentially be an issue. But if everything looks good and all readings on the pressure gauge are within normal ranges, then this is a sign that your catalytic converter is functioning properly.

Step 11: Final Diagnosis

Once you have completed all of the above steps you should have a good indication of whether or not your catalytic converter needs to be replaced. If it does, then a professional mechanic should be consulted in order to properly install the new unit and get you back on the road as soon as possible! 

It is also important to note that regardless of the outcome, you should always follow all safety recommendations when performing automotive repairs. Always wear safety glasses and gloves to protect yourself from any possible hazards.

By following these steps for how to check catalytic converter with scan tool, you can easily diagnose any issues that may be present in your car’s emissions system and make sure that your car is running at its best. For more information about getting the most out of your car’s performance, make sure to read our other blog posts or consult an experienced mechanic for further assistance.

Do You Need to Hire a Professional?

Although you can check your catalytic converter with a scan tool, it is advised that you seek professional help if the issue persists. A professional mechanic will be able to accurately diagnose and repair any problems with your car’s emissions system so that you don’t have to worry about further issues down the line.

It is also important to note that a professional will be better equipped to handle any potential safety hazards associated with working on a car’s emissions system.

How Much It Could Cost?

Scan Tool Are Depend on the Severity of the Problem

The cost of diagnosing and repairing your catalytic converter with a scan tool will depend on the severity of the problem as well as the type of car you are driving. The labor costs associated with this process can range from $50 to over $130 depending on where you take your car for service. In addition, parts such as new oxygen sensors or a new catalytic converter can add up quickly so it is important to budget accordingly.

Frequently Asked Questions

Q: Is It Possible to Check My Catalytic Converter With a Scan Tool?

A: Yes, it is possible to use a handheld scan tool in order to diagnose any issues with your catalytic converter.

Q: What Should I Do If My Car is Having Emissions Issues?

A: If your car is having emissions issues, it is best to consult a professional mechanic in order to accurately diagnose the issue and determine the best course of action.

Q: How Often Should I Check My Catalytic Converter?

A: It is recommended that you check your catalytic converter at least once a year or every 10,000 miles in order to ensure optimal performance and avoid any potential safety hazards.

Q: What is the Difference Between A Scan Tool and an OBD-II Reader?

A: A scan tool is a handheld device that can be used to diagnose issues with your vehicle’s emissions system, while an OBD-II reader is a device that reads the car’s onboard computer for any fault codes or sensors. While both devices can be used to check your catalytic converter, a scan tool is typically more comprehensive.

Reads the Car’s Onboard Computer


In summary, checking your cat converter is an important task for any car owner to stay on top of. With the tools listed above, you have all you need to detect a potential problem early on and help ensure longevity and health for your vehicle. It’s never been easier — so don’t forget to check over your catalytic converter frequently!

Furthermore on how to check catalytic converter with scan tool, if any problem arises during the diagnosis or repair process then do not hesitate in seeking professional help and taking advantage of their expertise. 

Investing a bit of time and effort into keeping up with your cat converter can save you a bundle down the road. So remember to diagnose, understand the issue, diagnose some more, then fix the problem in order to keep your car running smoothly all year round!

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Enrique Howard

Hi, I am Enrique. I started my professional life as a handyman and did a lot of external and internal repair of home and office with a little bit of electric and plumbing support. I have extensive experience in tools testing such as drilling, turning, milling, and non-conventional machining like EDM. So let me help you on your journey towards becoming an enlightened DIYer with amazing tools that you can use on your project.

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