[s-cars] Multifuntion sensor Q's.&In-Reply-To=

[Mike Claire]

Sorry, the very next unread email was Calvins, which shed some light -

"Yes, the temp gauge is a completely different output from the MFTS than the
temp sensor that controls the fuel mixture.  I think you can find the
reading on the one that controls the fuel mixture through the climate
control system back door."

So my takeaway is - next time my car is at operating temp, but the coolant
temp gauge reads zero, use the climate control to determine what temp the
ECU is working from.  If it's a good temp, then no worries about
unnecessarily rich mixture.  It just means I don't have a temp gauge.  Not a
big deal.

That answers that.  But if somebody wants to tell me where to check voltage
to diagnose the problem with my temp gauge, that would be great!



Mike




On 3/26/07, Mike Claire <mike.claire at gmail.com> wrote:
>
> Sorry for the hijack.  But which sensor controls the coolant temp gauge?
> I thought it was the MFTS, but now I'm not sure.  If it matters, mine's a
> '93.
>
> If the coolant gauge reads zero, but the car is at operating temp, at
> which sender do I check for voltage - the MFTS, or the G62 coolant
> temperature sender?  Any details on which pin, and what I might expect for
> voltage would be a great help.
>
> My coolant temp gauge is intermittent and I figured it was probably a cold
> solder joint in the cluster PC board, so I was willing to let it slide.  But
> if it's a sensor, and if that means the ECU gets the same reading as the
> gauge (zero) about 1/2 the time, it wouldn't be cool if the ECU is telling
> the car to run extra rich during normal driving.
>
> I do see a little soot on the back bumper (pearl) if I don't wash the car
> for a couple weeks.  I figured that was just my Pastore 1+ chip (MTM) doing
> its thing (rich mixture on boost).
>
> The gauge is either awake, showing the right temp, or asleep, reading the
> same as it would with the ignition off.  It goes back and forth, every 15
> minutes or so.  My mileage is same as always - 20-22 mpg in a good mix of
> highway/around town driving, making good use of the turbo.
>
>
>
>
> Mike
>
>
>
> On 3/25/07, Dave Forgie <forgied at ae.ca> wrote:
> >
> > Paul: Calvin's answer is spot on.  If you need more info, follow the
> > link below to my UrS4/S6 FAQ page on AudiWorld.  The link leads to info
> > about the MFTS and its role in the 3B and the AAN and the role of the
> > G62 coolant temp sensor that is likely your problem:
> >
> > http://forums.audiworld.com/s4s6/msgs/150040.phtml
> >
> > The climate control codes (to compare the coolant temp from the MFTS to
> > that from the G62) is Channel 51 at:
> >
> > http://www.12v.org/maintenance/index.php?section=tr&ss=hvac&ch=ccodes
> >
> > HTH
> >
> > Dave F.
> >
> >   the G62
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> >
>
>