# got 4-1 header installed but now getting p0420 code



## JOHNYSLEEPERB15 (Aug 28, 2009)

after todays of driving.. i get P0420 TW (Two-Way) Catalyst System, Bank 1 error.. 

i had 4-1 header installed to remove pre cat. with 2 O2 spacers.. 

why the heck am i getting this error..??

i have reset twice and it keeps coming back..


----------



## saint0421 (Sep 24, 2006)

where did you place the o2 spacers exactly?


----------



## JOHNYSLEEPERB15 (Aug 28, 2009)

i had a exhaust shop do the job for me.. its not his first time installing it.
i don't see anyspacers between o2 sensor and 4-1heater.. there is as other hole on top of o2 sensor and its plugded up with a bolt.. 

i am going to get pictures..


----------



## chimmike (Oct 17, 2002)

this is going to happen unless you get the 02 fooler, or ghost. I can't remember what it's called. Either way, it's just a code. The post-cat o2 sensor is essentially a worthless sensor as part of OBD2 monitoring of emissions controls. Useless crap.


----------



## JOHNYSLEEPERB15 (Aug 28, 2009)

chimmike said:


> this is going to happen unless you get the 02 fooler, or ghost. I can't remember what it's called. Either way, it's just a code. The post-cat o2 sensor is essentially a worthless sensor as part of OBD2 monitoring of emissions controls. Useless crap.


yeah ,, i know.. its just if this light is on conssistanly and other issue arrises .. ses light will not notify me.. you know what i mean..


----------



## Faja (Aug 31, 2009)

chimmike said:


> this is going to happen unless you get the 02 fooler, or ghost. I can't remember what it's called. Either way, it's just a code. The post-cat o2 sensor is essentially a worthless sensor as part of OBD2 monitoring of emissions controls. Useless crap.


I think someone just had a post on installing the anti-fouler, I think that's what you're talking about. Johny, do a search for "anti-fouler" and you'll find the installation procedure. I think that will take the CEL off.

Here it is: http://www.nissanforums.com/qr25-2-5l-engine/157046-02-cheater.html


----------



## chimmike (Oct 17, 2002)

JOHNYSLEEPERB15 said:


> yeah ,, i know.. its just if this light is on conssistanly and other issue arrises .. ses light will not notify me.. you know what i mean..



this is the real ultimate truth of OBDII. All those codes that could pop the check engine light are merely for sensors of the exhaust/emissions system thanks to our strict federal regulations, and a magnet for dealer repair shops. Check engine lights to car-dumb people mean "OH CRAP! GET TO THE DEALER FAST!" which means an instant $60-120 for the dealer to scan the code. Meaning they get paid big bucks for some lackey to plug in a code scanner.

If something seriously goes wrong with your car, you're going to know it. You won't need any check engine light to tell you. The motor will act funny, steering might go out, weird sounds, whatever. You'll know.

Find a real car repair joint where the guys check codes last, and listen to the engine and the customer first. Hang out there, and you'll get a good feel for repairs, problem diagnostics via methods other than computers. Fortunately for us, cars ran without computers for decades and some of those mechanics are still around


----------



## JOHNYSLEEPERB15 (Aug 28, 2009)

i hate stealer ships!!!i use to work as part adv. for toyota.. i know how they run.. but it;s just finding a good lil shop mechanic that you trust that is hard.. 

anyways.. anybody see a fucking spacer here.. fucking shop didn;t use it, am i correct.. but no biggie.. as long as he didn;t throw is out..and connect is back in for me..


----------



## chimmike (Oct 17, 2002)

nope, no spacer there. just the bung.


----------



## saint0421 (Sep 24, 2006)

spacers are supposed to go on the secondary o2 sensor anyhow. It looks to be the primary o2 sensor in your pictures there.


----------

