2015 SONIC CODE P0420

[Emma’s sonic]

Thank you @31003 for posting your troubleshooting technique and how you found the leak. I have a 2013 1.4L (~170k miles) that intermittently sets the P0420 code. I replaced the front pipe ~5years ago because the bellows had a crack in it. I will see if the weld has broken on the newer pipe. There's nothing more aggrivating than having that little yellow engine light come on.

Hi, and sorry to jump in so late. But which pipe exactly do you mean by front pipe? Is this the pipe just before the cat?
Thanks in advance

Ray