Car runs too cool/intermittant autocheck annoyances
pjrose at frontiernet.net
Sat Oct 22 19:01:40 EDT 2005
At 1:55 PM -0700 10/22/05, Aaron Rosenstein wrote:
>After a 5 year break from Audis, I got the bug again and picked up a
>nice 91 200tq from a local seller. The car is in amazing shape overall,
>and has less miles than my last one, but still ahas a couple quirks.
>I'm concerned that the engine seems to runn so cool. Unless I'm driving
>around town slowly, the temp needle never get off the bottom three
>lines, and my last car always ran just under half even on teh freeway.
>At the same time, I get the annoying intermittant overheat/water symbol
>on the autocheck box,
Glad to hear people are still buying these cars! ;-)
Don't disconnect autocheck (especially when you might have a temp
gauge that's not working properly), but instead find and fix the
source(s) of the problems.
A defective MFTS (multifunction temp sensor) can cause both the low
temperature reading _and_ the gratuitous warning for low-coolant
level. If a bad MFTS is the source of the problem, the chances are
that the A/C compressor won't work and that the max boost is low
(e.g., 1.4 bar). Anyway, to test the MFTS, pull the connector off
(i.e., disconnect) the sensor: if that's been your problem, then the
low-coolant warnings will stop (for sure), the maximum boost pressure
may increase (assuming there're no other problems) and the A/C might
work (if refrigerant pressure is OK). Of course the temp gauge will
be dead. Simple matter to then replace MFTS.
The brake pad warning goes off when there's an _open_ sensor circuit.
Fixing the brake pad warning is often just a matter of properly
shorting the sensor connector wires (if the sensor circuit been
defeated by a PO), or correcting a poor contact in one or both of the
connectors (if you actually are using pads with sensor connections).
Oil gauge warning could require oil pressure sensor replacement as
mentioned by Chuck.
Phil Rose Rochester, NY USA
'91 200q (153K, Lago blue)
'91 200q (64K, Tornado red) mailto:pjrose at frontiernet.net
More information about the 200q20v