CEL on a Focus Help
 

My neighbor has a 03 focus with a 2.0

well yesterday it threw a CEL and she wanted me to check it out. I took it to Autozone to put a scanner on it and came up with a P0171 - System to Lean Bank 1.

The lady at autozone says that normally means needs a tune up. Well I know needing a tuneup wont throw a CEL for being Lean, It would be to rich correct?

Also does anyone know of any common causes for this CEL.

Any help would be appreciated.

THANKS,
Ben

she is wrong.

next thing you need to do is determine which part of the fuel map (loaded or unloaded) is being compensated for by increased pulsewidth in your fuel trims. Check with a scanner the live data and see where your long term fuel trims are positive (because its adding fuel) - either at idle, or under load (like driving down the highway going 55)

oh

and I made this thread but none of the mods stickied it, which they should have.

https://www.ranger-forums.com/f18/ad...1-p0174-96793/

Awesome thanks for that. I told her what it might be and Unfortunately i dont have a scan tool... So she said she is gonna take it to AAA tomorrow... Ill let you know what it turns out to be.

I would rather walk then own a car with no scanning software.

haha I wish I could afford a ford scan tool

you don't need one. go buy any scanner for 100-200 that has live data and you can view the fuel trims. Fuel trims are so important.

Gotcha

fuel filter needs to be changed....

Go over to Focaljet or Focusfanatics Both websites are great.

MINE WAS A O2 SENCER