[V8] Coolant Temp Sensor Values (was New O2 Sensor- Whhhhaaaatt)

Tue Jul 18 15:27:55 EDT 2006

I guess that makes sense - and from the description you give, the thermal switch
looks like it has three positions, which just about has to translate to three
different resistances. That may explain the odd resistance number for the 20
degree step.

It seems far simpler to just use the existing guage temp sender for the ECU -
but then that would not be the "Audi Way".

Dave

Quoting Ingo Rautenberg <i.rautenberg at waratap.com>:

> Dave,
>
> No, they're two different sending units.  According to ETKA, the rear
> one (white housing) PN# 035 919 369 M Thermal switch -10/20/80 C  2
> pin M14x1,5
>
> The front one is 077 919 501 (black housing) temperature sender 120 C
> also 2 pin M15x1,5
>
> HTH
>
> On a side note, I'm wondering if I'm developing too much fuel
> pressure in the system, as I hear more and more the purging/whistle
> sound of a valve by the rear of the car by the tank and I always have
> a nice pressure of escaping air when removing the fuel cap.  Much
> more so the with the '91.  This is in the '93.
>
> Ingo
>
> On Jul 18, 2006, at 11:14 AM, dsaad at icehouse.net wrote:
>
> > I think the sensor at the right rear head (for the ECU) and the
> > sensor at the
> > left front head (for the guage) are the same part number - right?
> >
> > If so, maybe there is a resistance/voltage chart for this sensor?
> > I seem to recall using this info to test the ECU sensor.
> >
> > I believe the Service Training Manual is the correct source of
> > information for
> > this one.
> >
> > Dave
> >
> >
> > Quoting Ingo Rautenberg <i.rautenberg at waratap.com>:
> >
> >> Hmm.  I have conflicting values here, guys.  I checked the Four
> >> volume manual and under the fuel or ignition section I confirmed it
> >> said that the coolant temp sensor at the back of the head should read
> >> between 1.46 and 3 Ohms (not k Ohms).  But according to the earlier-
> >> released Service Training Book with the graphic scale chart, this
> >> MUST be a typo.
> >>
> >>  From what I can discern, according to this, the values should be ~
> >> 2k to 3k at room temperature.  This value drops to ~90 Ohms at 130 C
> >> and rises to ~ 6k at 0 C / 32 F and up to 13k at -22 F / -30 C
> >>
> >> Anyone want to confirm?
> >>
> >> On Jul 17, 2006, at 2:56 PM, Ingo Rautenberg wrote:
> >>
> >>> Steve,
> >>>
> >>> Since i'm at work right now I can't verify.  But that's what I
> >>> recall
> >>> from the Factory Manual reading of yesterday.  Yeah, I looked twice,
> >>> too.  I thought the resistance value would/ should be much higher...
> >>>
> >>> Will recheck when I get home.
> >>>
> >>> On Jul 17, 2006, at 2:33 PM, Buchholz, Steven wrote:
> >>>
> >>>> ... you can infer the values from the OBD section on the EFI
> >>>> system.  The coolant temp sensor is one of the ten parameters that
> >>>> the ECU logs.  I can read the values out using ProDiag ... should
> >>>> also be possible from VAG-COM.  The advantage of using this method
> >>>> is that you see the value that the ECU sees ... and you don't get
> >>>> your hands dirty ... or burned!
> >>>>
> >>>> It is a bummer to hear that the value is so low ... are you sure
> >>>> this is right Ingo?  Resistance measurement in such a low range is
> >>>> prone to errors due to connector resistance.
> >>>>
> >>>> Steve B
> >>>> San José, CA (USA)
> >>>>>
> >>>>> Yes to the sensor on the back of the head.  The initial Service
> >>>>> training document even has a graphic on the proper sensor Ohm
> >>>>> readings, which, surprisingly are not in the four book volume.
> >>>>> There
> >>>>> it only states that the sensor reading on a 'cold' engine at room
> >>>>> temperature should read between 1.5 and 3 Ohms.  (mine read at
> >>>>> 1.46 -
> >>>>> close enough).  Now I need to check the resistance when it's
> >>>>> hot...
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> >
> >
> >
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>