!@#$%^ code 420

silentneon01 · Post by **silentneon01** » Sun Nov 25, 2007 9:55 am

its a great freaking code for an exhuast problem.

Ok I've changed both o2 senors. I changed the cat to a high flow cat last year. I've changed plugs and wires. But I'm still throwing code 420 wth....

Anyone got any ideas

2001 dodge neon 140K
AEM CAI
F/X UDP
R/T dual outlet exhuast

gilly02le · Post by **gilly02le** » Sun Nov 25, 2007 10:54 am

upstream o2 and downstream o2 must see a difference in readings, or this code will be present. So, is your lower o2 sensor, before your cat by chance?

Cbussilver01es · Post by **Cbussilver01es** » Sun Nov 25, 2007 1:15 pm

Your cat is probably clogged, I kept throwin that code like crazy when my cat was clogged. I think its because your upstream and downstream o2 are reading the same,

tho Im not completely certain.

kevo · Post by **kevo** » Sun Nov 25, 2007 3:11 pm

considering you have a high flow cat, did you use the non fouler trick with it?

silentneon01 · Post by **silentneon01** » Sun Nov 25, 2007 3:19 pm

kevo wrote:considering you have a high flow cat, did you use the non fouler trick with it?

No what do I have to do?

and downstream is in the cat.

Cbussilver01es · Post by **Cbussilver01es** » Sun Nov 25, 2007 6:08 pm

http://forum.2gn.org/viewtopic.php?t=1025
^Non Fouler trick

Kevo wrote:considering you have a high flow cat, did you use the non fouler trick with it?

Now I thought if you were running a gutted cat or a high flowing cat w/o the non fouling mod, you'd be getting a P0141 or P0140 instead of the P0420 code