On 2001 e320 a rattling noise is coming from converter can tighten it up

could be a failing cat converter and the code would be refering to a roblem heated oxygen sensor (HO2S) in an exhaust manifold before the cat converter
have an exhaust shop check the cat converter as they do break up internally , rattlr around and in some instances can block the exhaust system

Usually this is caused by the exhaust, and most common is the heat shield around the catalytic converter. Sometimes these can be spot welded, by I have fixed a few by putting together a few large stainless hose clamps and placing all the way around the unit and tighten them up. Sometimes the rattle is internal, and replacement is the only option. If so, rather than getting a very expensive stock replacement, you can by a universal easy flow hot rod type for about $100, plus installation.

Check catalytic converter.Catalytic converter could be breaking up inside.

It is most likely an exhaust heat shield or a catalytic converter that is breaing apart inside. Get underthe van when it has cooled off and "thump" the exhaust with your fist to see if you can locate the rattle. Often, the heat shield welds break where they are attached to the catalytic converter. I have fixed many of them by taking 2 or 3 large screw-type hose clamps and screwing them together to make them long enough to reach all the way around the catalytic converter and tighten them down to stop the rattle. If the noise sounds like it is coming from INSIDE the converter, you will have to replace the catalyst. (or ignore the noise)

it can be from a heat shield on your catalytic converter or the converter itself going bad. the best way is let someone hear where it is coming from when you are pusing the gas, good luck

Good evening.
If this is a tinny type of rattle and it only happens at certain RPM's I would look for a loose heat shield over the exhaust pipes. Have someone apply the throttle until the rattles begins and listen under the car with a long screwdriver or a yardstick. Use the screwdriver to push on the various shields surrounding the manifold and pipes until the rattle stops. then use a hose clamp or two to tighten them up.
Also I see a lot of catalytic converters that become loose internally and rattle around inside it.
The only cure for that is to replace the converter.
If this rattle is an internal engine noise you should have an experienced mechanics ears give you an opinion.

Thank you for using FixYa.

KL

The metal shielding around your catalytic converter could be rattling or the rubber donut that holds the rear tailpipe could be bad. When your car is cold shake your tailpipe and see if you can reproduce the noise. If you can your tailpipe donut is likely bad. Three dollars at any auto parts store. If it does rattle when you shake your tailpipe then the heat shield for your convert could be loose. You need to tighten it up another piece of metal between it and the converter to keep it from rattling. If you hear the rattle when you go over bumps too then your exhuast is probably, loose. Crawl under there and stake shaking things, I am sure you'll find the problem

hi you can try removing the door panel and putting in some sponge at the top of the door inside, do the window right up and glue it in place you will have to measure the gap between the door and the window as you do not want too thick sponge as this will hinder the window coming down this should cure the rattles have done this with my own bmw and seems to work well....hope that helps

Have you checked the catalytic converter (also reffered to as simply a Cat by mecanics)? It's the first big canister you encounter on the exhaust line right after the manifold and before the resonator and/or muffler. After a while rust and time can cause either the casing itself to come loose and rattle, or the insides themselves break up and rattle around the cat. And being where it is it often resonates sound around the engine compartment, making it seem the sound is coming from elsewhere than it actually is. And while your at it don't forget to check the flex pipe usually connected to the cat also (some models do not have a flex pipe though). If all that is fine, then the other things to check would be the accessory brackets, wire holders and the like. With vibration and time, sometimes they loosen up and start to rattle. Still nothing? check the suspension parts for anything loose (IE. sway bar links, coils springs, tie-rod, suspension tables). Other than that there isn't much in there that can rattle. If you look at how an engine is built, you'll see that there isn't much inside that can rattle around without causing the engine to fail altogether. I'm not saying it can't happen though, but it's highly improbable. Hope this helps

If this sounds like a tin can rattle it is likely a loose heat shield on top of the catalytic converter. They come loose after time and corrosion take their toll.