My first CEL - Catalyst Efficiency below threshold?

edkwon · 06-14-2004, 11:20 PM

Here's my setup:

UTEC stg 2, TXS TBE with single hi-flow cat, velocity stack intake, JDM Sti TMIC. I had most of this installed a couple months ago and tuned. I haven't had a CEL until today when i was just cruising along highway speeds. I pulled the code and this is what came up:

P0420 Catalyst Efficiency below threshold

anyone know if this is a major problem or something that is normal with my mods. I've reset my ECU and just waiting to see if it comes up again.

Ed

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edkwon · 06-14-2004, 11:40 PM

Ok after doing some reading, i found this is the error code i'd get if i ran the catless race pipe. I wonder if my cat is going bad for some reason.

Ed

timo · 06-15-2004, 09:43 AM

there's probably nothing wrong with the cat, as p0420 is expected with only one high flow cat instead of 3 normal ones

When I replaced my uppipe and downpipe and drove for a few thousand miles I got the cel as well, but now that I have the accessPORT it's gone(the port takes care of it)

BeeGee · 06-15-2004, 10:04 AM

Yep, I got it after installing my Stealthback w/high flow cat and uppipe. I called TurboXS and they said probably 30% of their customers got the CEL with just the SB, and just about everybody got it if they added a catless uppipe to the mix.

The good thing is that the bung on the SB is located perfectly for installing the mechanical O2 sensor fix which will eliminate your CEL without the need to do any splicing of your sensor.

edkwon · 06-15-2004, 12:18 PM

ok thanks, luckily this happened right after i got my car inspected, so no OBDII scan hassles

Ed

mbiker97 · 06-15-2004, 12:39 PM

Ed: Check out the mechanical fix. It will get rid of that pesky P0420 CEL.

http://forums.nasioc.com/forums/show...hreadid=424666

mixup52 · 06-15-2004, 04:55 PM

Or you can find one on Ebay. This code has to do with the removal of your Downpipe cat. Has nothing to do with your high flow cat. I have done the mechanical fix and it works great.

Chris

Celly · 06-15-2004, 07:59 PM

Crazy Question.... I thought the UTEC Blocked this code? No?

Uncle Scotty · 06-15-2004, 08:13 PM

Quote:

Originally posted by Celly
Crazy Question.... I thought the UTEC Blocked this code? No?

NO....you CAN disable the Check Engine Light.....but THAT would be very VERY foolish.

On the P0420 CEL....do the 'mechanical' CEL fix for the rear o2 sensor and done.

Celly · 06-15-2004, 08:27 PM

Quote:

Originally posted by Uncle Scotty
NO....you CAN disable the Check Engine Light.....but THAT would be very VERY foolish.

On the P0420 CEL....do the 'mechanical' CEL fix for the rear o2 sensor and done.

I hate you.

Perhaps we can get the TurboXS guys to block it. They are smart dudes. This would just give me another reason to lust after the utec...

BTW: 4 - 5 Car starts, and this CEL goes away...

Macabre · 06-15-2004, 08:33 PM

The UTEC has no way of knowing what's going on in the ECU to cause the CEL to come on. They just disable the thing completely if you want that. There's plenty of easy ways to do away with this specific code. I've been catless for about a year with nary a CEL.

mixup52 · 06-15-2004, 11:20 PM

But you need the cel with the utec to know if you are knocking.

Uncle Scotty · 06-16-2004, 06:59 AM

Quote:

Originally posted by mixup52
But you need the cel with the utec to know if you are knocking.

If you set it to 'disable', the ONLY time it will flash is if you knock(or have a misfire....I think).

THAT is why it is a BAD idea to disable it.....

06-14-2004, 11:20 PM	#1
edkwon Scooby Specialist Member#: 453 Join Date: Oct 1999 Location: 小さいӔ Vehicle: 2013 VT	My first CEL - Catalyst Efficiency below threshold? Here's my setup: UTEC stg 2, TXS TBE with single hi-flow cat, velocity stack intake, JDM Sti TMIC. I had most of this installed a couple months ago and tuned. I haven't had a CEL until today when i was just cruising along highway speeds. I pulled the code and this is what came up: P0420 Catalyst Efficiency below threshold anyone know if this is a major problem or something that is normal with my mods. I've reset my ECU and just waiting to see if it comes up again. Ed * Registered users of the site do not see these ads.

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06-14-2004, 11:40 PM	#2
edkwon Scooby Specialist Member#: 453 Join Date: Oct 1999 Location: 小さいӔ Vehicle: 2013 VT	Ok after doing some reading, i found this is the error code i'd get if i ran the catless race pipe. I wonder if my cat is going bad for some reason. Ed

06-15-2004, 09:43 AM	#3
timo Scooby Newbie Member#: 43949 Join Date: Sep 2003 Location: Roswell, GA Vehicle: 2003 WRX WR Blue	there's probably nothing wrong with the cat, as p0420 is expected with only one high flow cat instead of 3 normal ones When I replaced my uppipe and downpipe and drove for a few thousand miles I got the cel as well, but now that I have the accessPORT it's gone(the port takes care of it)

06-15-2004, 10:04 AM	#4
BeeGee Scooby Specialist Member#: 27724 Join Date: Oct 2002 Location: Raleigh, NC Vehicle: 2003 WRX Wagon Silver	Yep, I got it after installing my Stealthback w/high flow cat and uppipe. I called TurboXS and they said probably 30% of their customers got the CEL with just the SB, and just about everybody got it if they added a catless uppipe to the mix. The good thing is that the bung on the SB is located perfectly for installing the mechanical O2 sensor fix which will eliminate your CEL without the need to do any splicing of your sensor.

06-15-2004, 12:18 PM	#5
edkwon Scooby Specialist Member#: 453 Join Date: Oct 1999 Location: 小さいӔ Vehicle: 2013 VT	ok thanks, luckily this happened right after i got my car inspected, so no OBDII scan hassles Ed

06-15-2004, 12:39 PM	#6
mbiker97 Scooby Guru Member#: 7922 Join Date: Jun 2001 Chapter/Region: MWSOC Location: Tucson Vehicle: 04 CTS-V b/b/b 99 GMC Highrider	Ed: Check out the mechanical fix. It will get rid of that pesky P0420 CEL. http://forums.nasioc.com/forums/show...hreadid=424666

06-15-2004, 04:55 PM	#7
mixup52 Scooby Specialist Member#: 39691 Join Date: Jul 2003 Location: Ogden Utah Vehicle: 2002 WRX Wagon White	Or you can find one on Ebay. This code has to do with the removal of your Downpipe cat. Has nothing to do with your high flow cat. I have done the mechanical fix and it works great. Chris

06-15-2004, 07:59 PM	#8
Celly Scooby Specialist Member#: 48724 Join Date: Nov 2003 Chapter/Region: South East Location: Dead Whorelando, FL	Crazy Question.... I thought the UTEC Blocked this code? No?

06-15-2004, 08:33 PM	#11
Macabre Scooby Specialist Member#: 3841 Join Date: Jan 2001 Location: Sacramento, CA Vehicle: 2004 WRX Wagon UTEC+VF22+WI	The UTEC has no way of knowing what's going on in the ECU to cause the CEL to come on. They just disable the thing completely if you want that. There's plenty of easy ways to do away with this specific code. I've been catless for about a year with nary a CEL.

06-15-2004, 11:20 PM	#12
mixup52 Scooby Specialist Member#: 39691 Join Date: Jul 2003 Location: Ogden Utah Vehicle: 2002 WRX Wagon White	But you need the cel with the utec to know if you are knocking.