n00b needs help; Computer reset?

[RedlegParatrooper]

Hi all -

Got a code: "P0171 system too lean bank one"

so, took truck to the Auto Skills Shop on post, (where we military types can do our own work and get access to shop tech and tools)

The dudes there looked up codes and confirmed what I thought which was Oxygen sensor.

Replaced Oxy sensor and disco'd the battery for the whole time I worked on the truck (3 hrs between sensor and new brake pads)

"check engine" light was off when I was done; Woo Hoo!

BUT: Check Engine light back on this morning. D'oh!

Please help!! What the hell?!? Do I need to have the computer reset another way?... Or?...

What gives?

Thanks!!

 

[adsm08]

You need to actually fix your unmetered air leak.

 

[superds]

After resetting the computer the codes disappear. After three drive cycles if the issue is still present it will trigger the CEL again. You may not have solved your problem by replacing the O2 sensor. I would look at the possibility of an exhaust leak upstream of the O2 sensor (even a very small one), I've heard that can also cause that code.

 

[adsm08]

I would look at the possibility of an intake gasket leak on the passenger side.

 

[superds]

I would look at the possibility of an intake gasket leak on the passenger side.

I agree with this. After I posted I saw your post I realized it is a better explanation than mine. The air leak could be anywhere from the MAF sensor to the O2 sensor but somewhere that would allow the most affect to Bank 1.

 

[adsm08]

I agree with this. After I posted I saw your post I realized it is a better explanation than mine. The air leak could be anywhere from the MAF sensor to the O2 sensor but somewhere that would allow the most affect to Bank 1.

An exhaust leak at the manifold has the potential to trip the P0171 code, but it is far less common than intake gaskets and usually accompanied by a distinct noise that gives away the exhaust leak.