The fuel tank pressure sensor is located right in the tank..... some may be
part of the fuel pump module itself but most that I have seen are a stand
alone sensor somewhere at the top of the tank in the "air dome" area.

I should have mentioned that the length of time required to set the fuel cap
light and/or the CEL can vary greatly with climate. It needs to be warm
enough to generate vapours from the fuel to pressurise the fuel system.
Where I live, we only have two or three months out of the year where the
EVAP monitor can complete.

You are quite right.... the fuel cap light will come on before the CEL. The
fuel cap light should illuminate as soon as the condition is seen and (IIRC)
the CEL needs to see the condition on two or three consecutive drive cycles.
No system is 100% perfect, least of all the EVAP monitoring system. If you
live where it is cold, the EVAP can't prove out and the light just wont
work...


"Kugar" > wrote in message
...
>I looked through the manual before posting, the manual only says that if
>fuel
> cap is not replaced or if it is not properly replaced, the fuel cap
> warning
> light will be lit and in due course of time will also trigger the CEL, and
> that
> once the problem is corrected, the CEL should go out after a period of
> normal
> driving.
>
> It also says in bold that it may take the system a LONG time to detect a
> missing
> or mis-applied cap.
>
> [My Thought] The fuel cap warning light should come on sooner than CEL, so
> that
> the vehicle operator could correct the problem before it triggers CEL.
>
> On gross inspection, I do not see any electrical connection to the cap or
> the
> fuel inlet where a sensor could have been.
>
> Matt
>
> ================================================== =========
>
>
> On Sun, 28 Nov 2004 06:56:36 GMT, "Jim Warman" >
> wrote:
>
> 'This sounds like a gnarly problem.... leaving the fuel cap off would
> 'constitute a gross EVAP system leak and should trigger the CEL if left
> 'unatended. At any rate, it will likely require some emissions systems
> 'diagnostics to find the cause. I'd suggest having the PCM scanned for
> codes
> 'and choosing the appropriate diagnostic routine for your findings.
> '
> 'FWIW... I see no mention of a fuel cap warning light in the WSM until
> '2002.... Perhaps your owners manual might shed some light on the subject.
> '
> '
> '"Kugar" > wrote in message
> .. .
> '> On my Ford Explorer 2000 EB's dash board, the fuel cap warning light
> comes
> '> on
> '> when I start the engine then goes out (just as other warning lights on
> the
> '> dash)
> '>
> '> BUT, it does not turn on if the fuel cap is NOT capped back on the fuel
> '> inlet.
> '>
> '> During the last week twice I forgot to cap the fuel inlet after
> fueling,
> '> there
> '> was no warning light on the dash, I discovered my mistake after
> reaching
> '> the
> '> destination, about 50 miles of highway driving..
> '>
> '> Where is the sensor for this light and where should I start looking to
> '> return it
> '> to normal function ?
> '>
> '> Thanks in advance.
> '>
> '> Matt
> '
>