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I have been told by a mechanic I need a special catalytic converter

He said my truck was built to be sold in CA, so therefore I have to have one specially ordered and it will cost about $1,000 to buy it and have it installed. Is this true? Are vehicles really built to only run on certain catalytic converters. I don’t live in CA, so don’t want to have to pay extra. Thanks!

Your car must be pretty old. Most cars have been “50 state” cars for years. This means every car could be sold in CA. You’ll need to tell us the specifics of your car - make, model, year, motor, trans, and miles on it would all help answer your question.

I would visit an exhaust specialty shop and see what they can come up with…Is passing an emissions test part of this story??

It is a 2004 Dodge Dakota, automatic trans and is showing only around 17k miles on it… but I’m getting a little suspicious about that now. I bought it “as is” as a first car for my son, but now he has joined the military and will be serving overseas so I want to fix it to sell it and give him the money. I didn’t realize it would turn into such a money pit. The catalytic converter was taken out and the pipes welded back together and the H2O monitor was also removed according to the mechanics. It runs fine otherwise.

V6 or V8? Here are a few cats for the V6.,carcode,1424494,parttype,5808

Thanks, appreciate it. Dang, but they are expensive. :confused:

You could always head to a scrapyard/used parts place and see what they have to offer. If the vehicle you’re pulling from is wrecked, then it’s most likely the cat is in decent condition as the engine would have been running.

No one will guarantee that part, though. However, it’s bound to be much cheaper. You can look for a really clean one. Depending on where you are, it’s possible to find one in good shape. Make a couple free phone calls and check.

Does it need to pass an inspection for you to sell it ?
If not , leave 'em off and sell it as is.

Heck, no inspections out here. I’ve even taken off the cats from four trucks over the years and sold them with no repercussions.

Humerous aside ;
They’re not H2O sensors…H2O is water :slight_smile: but we know what you mean. By the way, it’s H-O2 sensor…heated oxygen sensor

It’s against EPA regulations (The Law) to sell a used CAT…But sometimes you can find them in the secondary market…

You can always sell the truck “As Is” and let someone else worry about it…

Is it? I swear I’ve seen at least one carried out of a yard down here. Personally, I’ve never had the need to replace one, so never tried.

I’m one to try and re-use parts whenever possible. Keep the amount of parts rusting down, and if they’re OK, use them - just in case you hadn’t guessed by now. :slight_smile:

Salvage yards is where I shop first, always…But most yards will have already pulled the CAT(s) and put them in the locked “high-value” bin…

Caddyman is right, it’s against federal law to sell a used c/c and carries a huge fine and possible imprisonment if caught.

You can always get a universal catalytic converter, which will be about half as much as the model-specific one. The downside is that you then probably have to have some custom exhaust work done to put it in.

What he said…Why not sell it as is

Universal for $55

“some welding may be required” = some extra installation $ will be required to leave your wallet (unless you DIY).

Go to and see what they come up with. But, you’ll still have to get it welded in place. You could go to an independent muffler shop. Sometimes they have really good deals.

2004 model year with 17,000 miles? The catalytic converter on your vehicle is covered by the 8 year/80,000 mile EPA mandated emission warranty. This means the dealer must install a new cataytic converter in your vehicle at no cost to you.


I think you would have a hard time getting the dealer to warranty a converter that has been removed from the vehicle and replaced by a straight pipe and the O2 sensor removed.

It is NOT illegal to buy or sell a used catalytic converter. However there are some hoops to jump through. If you choose not to jump through them, chances are you will never get caught. After all, the car was that way when you bought it, right? Whoever removed the converter probably violated the law, though.

Here is what the EPA says about the law:

You need to comply with the equipment requirements of the state you’re in. Walker sells a direct fit twin cat replacement with a Y pipe…basically a bolt up replacement for the whole shebang for $395. Add in an hour of labor to R&R and you’re done.

The sensors that were removed are not H2O (water), but rather O2 (oxygen sensors). Without them, your truck will run in open loop and, likely, run rich and waste fuel. The O2 sensors tell the Engine Control Unit how much unburnt oxygen is in the exhaust gas. If there is too much oxygen, the computer adds more fuel to the mixture. If it smells too little oxygen, it pulls fuel and leans out the mixture. Without the O2 sensors talking to the Engine computer, the computer runs the engine on a default map that errs on the rich side so as not to damage the engine by running too lean, hot and possibly detonating.

If you replace the cats, you should add the O2 sensors if they aren’t already there. Cats don’t like a rich mixture and will die an early and expensive death without them.

All four O2 sensors will set you back under $200 here:

Be sure to order the direct fit ones. you should be out the door well under $1,000, maybe $800 - $850-ish?

Good luck,

Brian C.