I am all for cheating IF you check everything and cannot fix it.

A vacuum leak can cause this, and since that can cause other problems it's worth checking for.

Also, an exhaust leak even after the converter can cause this code.

Dave

 

I think your mechanic is wrong and whaty he told you is exactly the opposite of reality with our cars (I'm assuming you have an Outback. Year? Miles?)

P0420 is VERY RARELY a failing cat.

It is most commonly a failing oxygen sensor (front Subaru, rear any brand), vacuum leak, exhaust leak or what not.

Search that code on the forums and you'll find plenty of info.

Cats rarely fail without serious mechanical problems, I think your mechanic wants to give you an expensive repair bill.

 

It's a 2002 subaru outback sedan 3.0.
126,000 Miles

From what I've been reading replacing the O2 Sensors usually just results in the P0420 code coming back on at a later time.

I don't think he's trying to take me for a ride he's helped me out a lot for free.

I will def check everything over for leaks and all.

In PA do they actually read the rear exhaust or do they just go off of the computer they plug into it.

I was also reading that my car year is known to be over sensative with it's readings. That normally nothing is to wrong for it to throw that code, so that's why if there are no leaks I'm going to just do the quick fix.

 

Pffft, it'sa a baby. Up near 160k on my '03 H6, only code thrown was for the TPS.

Dave

 

I agree. Mine will roll over 200K miles later today. I'm now half way to 400K !!!

Only code I've ever had in mine was also for the TPS.

 

Can anyone answer those questions please?

 

Do you mean, if you could install that cat yourself?

Those bolts can be difficult- but that is a 4cyl cat. Won't fit, I believe.

Dave