im coming home from work last night and my service engine soon light comes on out of no where.
so this morning i take it real quick to get code retrieved.
its saying i have a bad o2 sensor.
so now im looking up the part for my car online.
the prob i have basically is that its showing me a:

1)Oxygen (O2) Sensor - OE Manufacturer
Part Number: DEN 2344430
Product Line: DENSO
IMPORTANT INFO: Rear of Converter,From 3/4/06

2)Oxygen (O2) Sensor - OE Manufacturer
Part Number: DEN 2344741
Product Line: DENSO
IMPORTANT INFO: Front of Converter

i see under importnant info it has one for front and one for rear?
do i need both?
i know this is kind of a dumb question , i just dont want to buy the wrong part.


i drive a 2006 oz rally lancer

im buying the parts from napa btw
all help will be greatly appreciated !

 

what code depends on if its front or rear, its usually front car has 2 one before first cat in manifold, and a 2nd before 2nd cat under car