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What part of the 2012 Toyota Prius exhaust system are these?

I’m looking for info on where, on my car, these parts came from.

I found them loose and resting on the heat shield of the exhaust sys (around the area shown in photo). I assume they came from my car, and I would like to put them back. But I don’t know what they are, or where/how they are installed, or even if they are suppose to be 1 or 2 peices.


Probably around that oxygen sensor. A good muffler shop can do the job easily.

Good catch! Parts of heat shields usually end up orphaned on the highway.

Thats the catalytic converter heat shield.Don’t park on long dry grass because it can catch on fire. Get it replaced ASAP.

Those heat shields are from the front exhaust pipe farther up from view, they are there to retain heat in the pipe for cleaner emissions. Nothing to do with grass as you can see that there is no heat shield on the catalytic converter that is closer to the ground.

Shouldn’t there be one? That’s very hot and close to the ground. I haven’t seen a cat without a heat shield below it, except when it fell off my Civic years ago. I saw it in my rearview mirror as it slid to the edge of the pavement.

The underside of a Prius.


Is that common nowadays?

That these parts are upstream (@Nevada_545) seems correct. But I looked up along the exhaust system but it wasn’t obvious where it mounted. Also, are these parts reusable or damaged? The edges with the notches seem rough suggested degradation due to rust. Or is it a welded part that broke off?

Finally, if it is intended to improve cat performance, can I assume that if car passes emissions, I do not have to replace it?

Find an independent muffler shop and let them take care of this . You don’t need fumes getting in your vehicle.

Pretty common. I buy catalytic converters for scrap, and see a lot that do not have a heat sheild. There may be a sheild between the cat and the body of the vehicle, attached to the vehicle.

These pictures are of a 2010 Prius that was in the shop. The heat shields are between the manifold flange and the primary converter. It will be difficult to weld in this location, the converter assembly will need to be removed to properly weld them back on. I would put the heat shields on a shelf in my garage, I don’t want a muffler shop fooling around with a very expensive Prius catalytic converter and I don’t want exhaust fumes leaking from a botched repair.

Thanks for info. Helpful.

UPDATE: I just complete NYS emission inspection WITHOUT repairing (i.e. replacing) the broken off shield and the car PASSED.

That is not something that they look for during an inspection and the test equipment isn’t sensitive enough to detect any difference in emission output.

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