P0420
 

Recently, I keep getting P0420. A few weeks back, I installed a Grimmspeed CAI, and the code came up not long afterwards. The downshifts in my '13 AT were rough, but once I cleared the code, it ran fine for about a week. Today, the code is back. I'm running catless header and OFT stage 2, V4.01 Beta. Most of the others on the forum that have had the problem was before a tune. Any suggestions besides checking that all the bolts are torqued to specs and upload the latest tune?

Rexspeed hood dampers will cause that every time … :sigh:


;)



humfrz

Dang it... was hoping for some HP gains.
:bonk:

Your computer is stoned.

It needs to share with me!!!

DTC is not disabled on the tune, hence it keeps throwing it.

Thanks, that is a lot easier fix. I'll give that a shot this evening.

I just uploaded v4.03. We'll see if that does the trick.

But, I still think there is something else going on. The same code was disabled by @steve99 and I ran with it for about 500 miles without any issues. Thanks again. I will certainly not getting rid of that file.

Anyways, could it be an issue with one of my oxygen sensors? I reused them when I replaced the header. With other cars in the past, I can read which one is bad.

No. P0420 is Catalyst System Efficiency Below Threshold (Bank 1). If you have no cat in the manifold you will get that DTC unless it is disabled. The newer OFT tunes did not have it disabled.

Thanks. That's what I was getting too. Strange thing is that my last tune did have it disabled, and I ran it for several months, then I got the code after I installed the intake.



Tuesday, I loaded the latest version. Today, I refilled my gas tank. So, that should be at least 230 miles on it. I would think that it would of showed up by now.