96 Tacoma: 0420 CEL Code after exhaust?

Hey guys,

My bro recently purchased a 96 Tacoma, 2.7L, 153k miles on it. One of the things we know it needed was a new exhaust system. We took it to an independent muffler place. They redid the whole cat back system, and the exhaust manifold. Apparently there was a crack in the manifold on both sides, so they just replaced it. As soon as my bro got it home from the shop, he noticed a 'stringy' white rope coming out of the tailpipe. He ended up pulling about 30' of fiberglass packing from the muffler. He brought right back to the shop, and the owner said he's never seen that before, but he would replaced the muffler. So my brother has had a very busy schedule, and hasn't had time to replace it till this afternoon.

Ironically enough this morning on his way to work he gets a CEL come on. I told him to run it to Autozone to get it read, and it's the 0420 code. He had it read after the muffler place swapped mufflers.

Now we're wondering if the code was from the muffler, or from something else? From what I searched on this code, it seems like a lot of people spend a lot of time and money to get rid of it, only to be disappointed. My bro doesn't want to spend a lot of money on it. We just bought about $100-150 worth of tuneup stuff (new plugs, wires, oil, air/oil/fuel filter, pcv valve, diff fluid, etc.) to tune it up soon.

We're just wondering what you guys think? What I said we should is disconnect the negative terminal to reset the ECU and hope it goes away, assuming it was caused by a faulty muffler. But I'm open to other suggestions, or possible explanations.

Thanks!

 

There are a few threads concerning the p0420 code, I get it myself once and a while. As yet I haven't seen a satisfactory resolution to it in any of the threads I have read.