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Old 06-14-2004, 11:20 PM   #1
edkwon
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Default 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
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Old 06-14-2004, 11:40 PM   #2
edkwon
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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
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Old 06-15-2004, 09:43 AM   #3
timo
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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)
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Old 06-15-2004, 10:04 AM   #4
BeeGee
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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.
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Old 06-15-2004, 12:18 PM   #5
edkwon
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ok thanks, luckily this happened right after i got my car inspected, so no OBDII scan hassles

Ed
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Old 06-15-2004, 12:39 PM   #6
mbiker97
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Ed: Check out the mechanical fix. It will get rid of that pesky P0420 CEL.

http://forums.nasioc.com/forums/show...hreadid=424666
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Old 06-15-2004, 04:55 PM   #7
mixup52
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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
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Old 06-15-2004, 07:59 PM   #8
Celly
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Crazy Question.... I thought the UTEC Blocked this code? No?
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Old 06-15-2004, 08:13 PM   #9
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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.
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Old 06-15-2004, 08:27 PM   #10
Celly
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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...
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Old 06-15-2004, 08:33 PM   #11
Macabre
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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.
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Old 06-15-2004, 11:20 PM   #12
mixup52
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But you need the cel with the utec to know if you are knocking.
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Old 06-16-2004, 06:59 AM   #13
Uncle Scotty
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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.....
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