Check Engine Light

My check engine light is on in my 2001 Focus SE. I have already changed the plugs, air filter, oil and filter and PCV valve, but it still on. The
mechanics in this area want around $70 to do a diagnostic, but I can probably replace the O2 sensor and EGR valve for not much more than that. Is the O2 the typical cause for the check engine light or is there something else that might also cause this? Thanks.
Joe
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consider taking it to AutoZone or the like. most of them will scan for free and tell you what it says.

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I didn't know they would do that. Thanks.
Joe

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Joe B. wrote:

Or check it yourself.
The Focus has a built-in test mode where it will tell you the stored code. Instructions can be found here:
http://www.focushacks.com/index.php?modid 
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Thanks Tony.

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If it works. My check engine light came on yesterday.
I don't get a DPTC code with this technique.
Good luck.
Joe B. wrote:

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wrote:

Wow, interesting page.
tom
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This just happened to me for the 2nd time on my 01 ZX3. Both times it has been the DPFE sensor and both times after it was fixed the check engine light comes on a day later for something else. First time was a fouled spark plug. The second time I will find out tomorrow.
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"SayWhat?" <whereeverforever.com> wrote in message

sensor all the way and it worked loose.
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"SayWhat?" <whereeverforever.com> wrote in message

An extremely common problem: someone else here might nicely supply the drill-down URL for more exact descriptions. Or just google on 'ford focus check engine light' or even 'focus DPFE' (I searched the latter more than a year ago when the issue seemed more .. burning...) to get a sense for how common ... (how nebulous?). ...
Last week was at least the fourth time for this happening on my wife's '01 SE. (I have decided to start checking the mechanics' name badges at our well-used and -abused local Ford dealership -- all these visits under warranty, BTW, at no charge to us -- to see if one of them might be named Godot ... Hopefully... ).
The time before, the mechanic was reportedly ecstatic that my wife remembered and could describe exactly how she was braking/clutching/shifting at the moment the light came on because "that was going to help" him figure it out. The time before that, the problem that tripped the engine light was reportedly not the fuel filler cap being badly seated, and not the fuel tank itself leaking in any way, but some tiny leak somewhere between the gas (petrol) cap and the fuel tank. I no longer remember the cause of the very first one. I only remember that I was driving it that time, and expended enough panic for both of us then, and for all succeeding occasions...
I will admit to great laziness here, in asking about the URL someone else in the thread supplied for what the error codes mean, a site I haven't visited: If you/we/I have these codes -- general knowledge, so to speak -- shouldn't/can't I just assume that this (reputable) dealership's mechanics are running off just to see the same codes each time, also? If so.... then, what? (!?) ... However he himself calculated them, the last mechanic (i.e., the 4th time) again, reportedly, said that more than 40 (different) glitches could trip that light.
Dave
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