re. Wont rev above 1500 RPM then cooled, continued.

[ben swann]

I just checked the wiring diagram.  There is an electronic thermoswitch
(MTFS?) and a coolant temp sensor.  There are leads from both switches
into the ECU/Ox control unit.  I'm not sure what switch function each
controls for the ECU.

You are also correct in that the electronic thermoswitch controls such
functions as the Coolant Temp Guage and the AC and is on the same
circuit as the coolant reservior level switch too.

Maybe this helps, as I didn't know that until I looked at the Bentley
diagram.

Ben
Ben



----- Original Message -----
From: Leif Karlsson <leif.karlsson at mbox332.swipnet.se>
Date: Sunday, June 8, 2003 6:05 am
Subject: Re: re. Wont rev above 1500 RPM then cooled, continued.

>
> It was (is) my impression that the MTFS *is* the sending unit for the
> temp. gauge (and some other things, like a warning light above
> 120C) and
> that the small one on top is connected to the fuel & ignition
> system. Is
> this wrong? It's the one on top that I replaced (and it was broken
> anyway).
>
> I fixed the wiring to the MTFS just weeks ago, that didn't change a
> thing (of course, the sending unit it self may be bad too).
>
> Leif
>
> ben swann wrote:
> >
> > Did you replace the Multi-Function Temp sensor (MTFS) on the
> bottom of
> > the cooling neck, or the sending unit for the temp guage?  The
> error is
> > a bad MTFS.
> >
> > Ben
> >
> > Date: Sat, 07 Jun 2003 14:34:56 +0200
> > From: Leif Karlsson <leif.karlsson at mbox332.swipnet.se>
> > Organization: Disorganization
> > To: quattro <quattro at audifans.com>
> > Subject: Wont rev above 1500 RPM then cooled, continued.
> >
> > Ok, Im still having trouble with this one.
> >
> > I have checked the idle switch: Works just fine.
> >
> > So I pulled the error codes. It told me that the temp. sensor is
> bad. I
> > also got an error code that I don't recognize: 3434 (or
> possibly, 4343),
> > anyone know what this on is about? Anyway, the last one don't
> seem to
> > appear again.
> >
> > So I replaced the temp. sensor, still no good: The old one was
> > definitely bad, the new one however gives me correct readings (about
> > 2500 then cold and ~300 then warm) but the ECU still tells me
> that the
> > temp. sensor is bad... And it doesn't run like it should then
> cooled, if
> > anything it runs worse like there wasn't a temp. sensor at al.
> >
> > Bad wiring comes to mind, is there a good way to test if the ECU
> signal> gets through al the way to the temp. sensor? Or is there
> something else
> > that can make the ECU think that the engine is warm then it
> really isn't
> > and therefor make it believe that the temp. sensor is bad?
> >
> > Any ideas are welcome.
> >
> > Best regards,
> >
> > Leif
>