P0420 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

KDad2 · 06-25-2018, 02:31 PM

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?

humfrz · 06-25-2018, 02:58 PM

Quote:

Originally Posted by KDad2

Recently, I keep getting P0420.

Rexspeed hood dampers will cause that every time …

humfrz

KDad2 · 06-25-2018, 03:27 PM

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

8RZ · 06-25-2018, 03:49 PM

Your computer is stoned.

KDad2 · 06-25-2018, 03:54 PM

Quote:

Originally Posted by 8RZ

Your computer is stoned.

It needs to share with me!!!

Kodename47 · 06-25-2018, 05:09 PM

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

KDad2 · 06-25-2018, 05:29 PM

Quote:

Originally Posted by Kodename47

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.

KDad2 · 06-26-2018, 12:51 AM

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.

Kodename47 · 06-29-2018, 04:34 AM

Quote:

Originally Posted by KDad2

Anyways, could it be an issue with one of my oxygen sensors?

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.

KDad2 · 06-29-2018, 09:39 AM

Quote:

Originally Posted by Kodename47

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.

06-25-2018, 02:31 PM	#1
KDad2 Senior Member Join Date: Jan 2014 Drives: 2013 Raven Location: Texas Posts: 485 Thanks: 202 Thanked 345 Times in 183 Posts Mentioned: 2 Post(s) Tagged: 1 Thread(s)	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?

06-25-2018, 05:09 PM	#6
Kodename47 Senior Member Join Date: Oct 2012 Drives: UK GT86 Location: UK Posts: 3,040 Thanks: 185 Thanked 1,633 Times in 1,113 Posts Mentioned: 156 Post(s) Tagged: 1 Thread(s)	DTC is not disabled on the tune, hence it keeps throwing it. __________________ .: Stealth 86 :. Abbey Motorsport/K47 Tuned Sprintex 210 Supercharger Kodename 47 DJ: Soundcloud / Instagram / Facebook

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06-25-2018, 03:27 PM	#3
KDad2 Senior Member Join Date: Jan 2014 Drives: 2013 Raven Location: Texas Posts: 485 Thanks: 202 Thanked 345 Times in 183 Posts Mentioned: 2 Post(s) Tagged: 1 Thread(s)	Dang it... was hoping for some HP gains.

06-26-2018, 12:51 AM	#8
KDad2 Senior Member Join Date: Jan 2014 Drives: 2013 Raven Location: Texas Posts: 485 Thanks: 202 Thanked 345 Times in 183 Posts Mentioned: 2 Post(s) Tagged: 1 Thread(s)	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.

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