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Unread 04-14-2012, 10:42 AM   #1
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2006 TJ Wrangler 
Join Date: Mar 2012
Location: clermont, fla
Posts: 24
P0431 warm up catalyst efficiency bank 2

2006 TJ wrangler 4.0
Code P0431
Warm up catalyst Efficiency Bank 2
Below threshold Confirmed.
Question is: how do I know where bank 2 is.. noticed mine has 2 little converters at manifold. Sensors before and 2 sensors after them.
Having low power and very poor fuel mileage.

chrome700 is offline   Reply With Quote
Unread 04-14-2012, 11:15 AM   #2
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1995 ZJ 
Join Date: Dec 2010
Location: Norman, OK
Posts: 2,006
Bank 1 is the front 3cyls, Bank 2 is the back 3cyls. The numbering system for the sensors is pretty easy, the first number is for the bank, the second number designates before/after cat.

HO2S-11 = bank 1, before cat or upstream from cat.
HO2S-12 = bank 1, after cat or downstream from cat.
HO2S-21 = bank 2, before cat or upstream from cat.
HO2S-22 = bank 2, after cat or downstream from cat.

here is a pic that might help.

jnicewan is offline   Reply With Quote
Unread 11-16-2012, 01:36 PM   #3
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2005 TJ Wrangler 
Join Date: Feb 2011
Location: aguadilla, puerto rico
Posts: 5
Did you ever fix the P0431 problem? My '05 Rubicon auto is throwing the same code. I am getting pretty low MPG - 9 in the city. It also feels sluggish on takeoff.
chasefsu is offline   Reply With Quote
Unread 11-18-2012, 07:51 PM   #4
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2006 LJ Wrangler 
Join Date: Oct 2010
Location: Grand Prairie, Texas
Posts: 420
Ive thrown this code a couple times and not sure if its due to being supercharged now. My Jeep is running fine so Im assuming its nothing major. Im going to datalog it and try the defouler method to see if it continues between now and when I get my dynotune.
Punisher8738 is offline   Reply With Quote

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