[V6-12v] Temp. gage reading low, trouble code 2312

[Tom Christiansen]

Scott,

Thank you for your swift reply. According to Bentley (and others) it IS
possible to change the thermostat without removing the timing belt. It's
just a royal PITA. But possible...

Tom

On Wed, 2004-01-14 at 12:34, Scott Thompson wrote:
> Tom,
> 
> I'd say it's very likely that it's the thermostat. This exact situation
> happened on both my wifes and my Dad's 96 A4s.
> The thermostat is not easy to get to.  You need to remove or at the least
> wrestle with the timing belt (check the archive over the last month, there
> were some posts on this).  I was able to buy a thermostat from a local parts
> store, but once finding that I needed to fiddle with the timing belt, I just
> had the TB and waterpump done too (It was due in 8k miles anyway), and
> returned the thermostat.
> 
> -Scott
> 
> 
> 
> ----- Original Message ----- 
> From: "Tom Christiansen" <tomchr at ee.washington.edu>
> To: "V6-12v List" <v6-12v at audifans.com>
> Sent: Wednesday, January 14, 2004 3:20 PM
> Subject: [V6-12v] Temp. gage reading low, trouble code 2312
> 
> 
> > Folks,
> >
> > The temp gage in my 1994 90S reads very low. On short drives (<15 min)
> > in the current 45-50 degree (F) weather the needle on the gage barely
> > makes it up to the minimum mark. Even after riding in stop-and-go
> > traffic for maybe 10-15 minutes followed by a short ride on the freeway
> > it usually doesn't make it higher than slightly below the second fat
> > mark at about 11 o'clock on the gage. On longer drives (one hour or so)
> > on the freeway the gage typically sits around or slightly above the
> > second small dot from the bottom. I have also been getting the 2312
> > trouble code indicating trouble with the Engine Coolant Temperature
> > sensor G62. I'm not 100% certain of the code number, but I am 110% sure
> > it was the ECT error code. The heat comes on before the needle reaches
> > the lower dot below the minimum mark on the gage.
> >
> > I changed the ECT sensor. The sensor which was in the car (suspected
> > faulty) had an amber or brownish-orange 2-pin connector. The replacement
> > had a white connector. Don't know if there is a difference between the
> > two. I've thrown the old ECT away... While changing the thing, I cleaned
> > the connector.
> >
> > I have paged through Bentley for procedures on how to test the ECT
> > sensor and the gage. I remember testing the new ECT sensor before I
> > installed it and it performed roughly like it should (the manual
> > mentions approximate values of resistance vs temperature, but I didn't
> > have a thermometer available to verify the ambient temp. I just
> > guessed...).
> >
> > For testing the gage, Bentley recommends messing around with ECT thermal
> > switch F76, which should be a 4-pin device located in the coolant line
> > behind the passenger's side cylinder head. I remember looking for this
> > without finding it at different time. Is Bentley on crack (wouldn't be
> > the first time!!) or have I just not looked hard enough? The only other
> > coolant temp. device I recall seeing is the huge thing in the bottom of
> > the radiator controlling the fan.
> >
> > Any suggestions on how to drive this gremlin away? Is this an obvious
> > case of stuck open thermostat? Or is it more likely to be an electrical
> > issue?
> >
> > If it turns out to be a thermostat issue, I suppose I'll need a new
> > thermostat and an o-ring (+ coolant). Are these dealer-only items or
> > should I shop around a bit? Any advantage/disadvantage of a non-OEM
> > thermostat?
> >
> >
> > Thanks,
> >
> > Tom
> >
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