P0430: What Does It Mean and How Do I Fix It?

When it comes to our diagnostics tool there are so many codes it’s tough to keep them all straight. Sure, you could hit the manual but those things read like stereo instructions so a little internet search turned you on to us, a site where we attempt to make the mechanics of your engine easier to understand and possibly fix yourself. 

That said, let’s take a look at code P0430 and find out how to take care of it. 

Code P0430

So you found a code P0430 and are wondering what that means for you and your engine. In short, this code means that bank 2 of your catalytic converter is not working cleanly. 

Most people, even those who don’t know the working parts of an engine, know what a catalytic converter is. They may not know how they function but, since they are stolen often, knowledge of their value is pretty common. 

What Is A Catalytic Converter?

Catalytic Converter
Image Source : wikipedia.org

This device in your engine takes the harmful gasses your engine emits and turns them into compounds that aren’t harmful to breathe. When your engine makes those little explosions it lets off hydrocarbons, carbon monoxide, and nitrogen oxide. 

Carbon monoxide is a gas that has no odor but can kill any animal that breathes air. Nitrogen oxides produce acid rain and smog. Hydrocarbons only produce smog but, if you’ve ever experienced it you know that’s enough of a hazard to warrant attention. 

The catalytic converter uses platinum and palladium to convert those destructive gasses into other, less damaging fumes. There are several ways it does this but, they all use the same principle, that platinum and palladium work as catalysts to these noxious gasses. 

There are ways your engine will let you know that there is an issue in that bank of your catalytic converter. 

  • A sulfur smell coming from your engine
  • Engine lacks power
  • Fuel economy has gone down
  • Check engine light comes on

Is It Important?

Catalytic Converter under car.

On a scale of one to ten, we would give this code a five or six. And, if you are familiar with our ideology when it comes to error codes for your engine then you know that we are going to suggest that you have this taken care of right away. 

Driving after you get this code will not cause any issues that put anyone into a dangerous situation. But, leaving anything unattended for too long can lead to bigger and more costly issues down the line. Plus, think of all the nastiness that your engine is letting out into the atmosphere. No one wants that. 

Getting To The Root Of It

There are several reasons why you are finding this error code on your diagnostics tool. The first is the most obvious reason while others dig deeper inside the converter itself. 

  • Faulty or old catalytic converter
  • Damaged air-fuel sensor
  • Damaged oxygen sensor
  • Exhaust system leak
  • Air-to-fuel ratio  is rich or lean 
  • Misfire (when one or more cylinders isn’t working correctly)
  • Using leaded gasoline
Mechanic repairman at automobile car engine maintenance repair work

On a side note, if your engine is misfiring then get that taken care of otherwise your converter will eventually break down. The same goes for using leaded gasoline, which can ruin a new catalytic converter.

How To Find The Problem

Step One

Use your diagnostic tool to check that you are getting a P0430. It’s always good to check again before you start working on it because other codes can come up and if they do, you should take care of those issues before moving on to the P0430. 

Step Two

Scan your exhaust system from one end to the other. Keep an eye out for cracks where there might be leaking or other damage that could be causing the failure. Areas you want to linger on include the gaskets, the exhaust manifold, and the pre-catalytic converter exhaust pipes. 

Step Three

Repair any leaks you find. Once all leaks are secure clear the code and complete a few drive cycles. If the code doesn’t come up you’ve fixed it! If it does then go to the next step. 

Step Four

Man inspection holding Battery Capacity Tester Voltmeter.for service maintenance of industrial to engine repair.In Factory transport automobile automotive image

This is when you need to bring out the big guns. Get your digital multimeter and check the voltage reading of the downstream O2 sensor while the engine is running. The downstream O2 sensor keeps track of the gasses your catalytic converter releases. 

When using the digital multimeter the ideal result would be a reading of 0.45V. That would mean that your catalytic converter is working perfectly. But, if you find that it is moving between 0.1V and 0.9V then it’s time for a new catalytic converter. 

Things To Look Out For

While replacing the catalytic converter might seem like the best possible solution there could be a trap set out for your next catalytic converter if you aren’t careful. If you see codes like P0300, P0301, P0302, P0303, P0305, P0306, P0307, or P0308 then that means that one or more of your engine’s cylinders are misfiring,

Other codes to look out for are P0174, P0171, P0172, or P0175. These are indicating that your fuel is rich or lean and this can also pose an issue for your new converter. All of these codes are signals that need immediate addressing otherwise you run the risk of ruining any new catalytic converter. 

How To Fix It

Mechanic troubleshooting a car engine

In the How To Find The Problem, we covered how to fix the issues you might find. Other than that we recommend you find a professional mechanic. The other codes that might come up are more complicated and might need an experienced eye. Otherwise, you can check our site for instructions on how to fix other codes that might pop up. 

The Cost Of Repair

As with most engine repairs, how much it will cost depends on the parts needed and the labor involved. Fixing a leak in your garage will run you much cheaper than having the local mechanic install a new catalytic converter. 


P0430 might not be a life-threatening code but it has its risks. Not only is the engine letting out terrible glasses for our neighbors, and ourselves, to breathe, letting things go only ends up costing more in the long run. We realize this is one of the more complicated issues we’ve covered so when in doubt, take the car in.

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