Calicab

so ive noticed over the past few days my mileage just going to hell, so i did all the regular stuff, tire pressure and all that. then it hits me, this same type of thing happened when my O2 sensor went on my last car but i dont have a CEL......hmmmm,

on my way to the parts store just to get a price on one, my check engine light comes on, yay. i get to the store and check the code and here is what i get.




so here be my question. is this simply the O2 sensor right off the header? or is this a circuit?as in wiring? has anyone gotten this code before?

i have the price on the sensor, and can have it in a day or 2, i just really need to know if its the sensor or something else.

also, bank 1/ sensor 1, im guessing that is the first sensor of the system, the one right on the header? makes sense to me, please correct me if im wrong
this little beauty?



thanks for any help guys

02-Lancer-Es

iTrader: (21)

My car has always thrown that code even with a new o2 sensor

Calicab

whats your mileage like? mine has dropped really fast, and as soon as it made a difference i noticed and couldnt fix, this code

RoadSpike

iTrader: (5)

Heater code those are the black wires on the 4 wire o2 sensor that heats the element.

Possible causes:

Direct short
Cut/Damaged wires

02-Lancer-Es

iTrader: (21)

Mine too , gets about 15mpg city and 19 hwy . But then again I'm turbo running 240whp

Calicab

yeah, that little blower might cause you to use an oz. or 2 more of petrol

4g94T

iTrader: (18)

I get 25 mpg with my 760cc injectors on 91 oct
But 12 mpg with E85 haha

senate6268

iTrader: (20)

I'm averaging about 35mpg with my 60 trim. What kind of tune are you guys running?

To the OP, check the wiring on the O2 sensor as far as you can trace it. Also, might be worth while to clean off any corrosion from your ground connections in the engine bay. They cause alot of issues when highly corroded.

OZ_kidd

couple things you can do is check if there is corrosion to the connection. unplug and assess. If not then just replace the whole o2 sensor. If your mileage is more than 75,000 might as well change it for the benefit of having a better mpg.

Calicab

so i replaced my upstream sensor and everything was fine. and then this


ive looked it up and found a few answers as to what this could be, either downstream o2 or CAT. i was just wondering if any of you guys have had this code personally and what you did.

its its the CAT im just going to say screw it and run a test pipe. but i wanted to get your guys opinion of it first.

just so you guys know where the car stands, it has 110,000 miles. im dont know when the cat might typically go to hell on these things

thanks for the help guys