Low level/high coolant temp. check light

[Pisobiker]

High guys

being very busy lately with job, family and.... stroker
Getting back to the forum every couple of days, but then I cannot keep up with all the new posts I find.....

Going to the topic:

Which sensors exactly is the "low level/high coolant temperature" check light on the on-board computer connected to?
My one started to flash almost all the time, sometimes even at start (engine cold). Cooling system is full and bled and water temperature on dash never shows more than 85-90°.
I've tryed to bridge reservoir's coolant level sensor without any change. Problem is ECU runs in Limp-home mode....

Thanks

Marco

[S2central.net]

From memory that light is driven by the 'high temp alarm' pin on the MFTS - the 3/4 pin jobbie underneath the water rail.

The coolant level switch is at the bottom of expansion tank.

If you are in limp-home, then it looks like the high temp alarm is active - this is also connected to the ECU. Check the pin-out on S2 Central.

Can't remember if the temp alarm is activated or cleared with an open-circuit (disconnected) MFTS - its worth a try...


Paul

[Pisobiker]

Yes Paul,

I thought the MFTS couldn't be the problem, 'cause I've already replaced it a few months back....
It is it again !!!!
Need to replace the plug as well. The plastic has become brittle.



Thanks a lot

Marco

[audiman]

open circuit will clear the limp home. It reverts to low temp. My sensor plays up. Sometimes the temp gauge works, sometimes it doesnt. Have replaced the connectors onto the switch and that didnt cure it. Thought it would as they had fallen off!!

[Mihnea]

Guys, this was Robo's problem too, even the meister Kim Collins himself couldn't fix the car after 3 weeks and £700 spent on various stuff, new hoses, blah blah blah...

Simply remove the wire that's responsible for this, I can't remember which one it is, but on the wiring diagram, it's the thermoswitch "high them alarm" wire, simply take it off the connector and leave it like this. You shouldn't have any more problems by doing so.

HTH,

Mihnea

[audiman]

That wont cure my temp gauge!!

[4WheelDrifter]

Kim Collins 'the meister'

[horvathg]

That wont cure my temp gauge!!

Tom,

on my 2,8 V6 coupe quattro the temp gauge always showed some 20 degrees lower than real. Once a guy remowed the whole instrumentarium and said that a voltage regulator transistor ( or tyristor...) connection on the upper right side of the back was sh....te. It took only ten minutes for him to make it work again. Said it was a typical Audi thing. I have to tell you that at that time the fuel level gauge was also tricking me.

[Mihnea]

Kim Collins 'the meister'

I'm not implying anything with that but it took me 5 minutes to figure the problem out and sort it out temporarily....

[S2central.net]

Yep - shows you how often he has to fault-find on the 20VT engine...
Reminds me of another specialist that spent weeks with an S2 that would not boost properly without checking that the fuse for WGFV was OK................

I'm not slagging here - it just proves you have to have your eyes well and truly open when you go to some of these specialists hoping for a miracle cure to running problems.


Paul

[AudiS2Au]

Yes Paul,

I thought the MFTS couldn't be the problem, 'cause I've already replaced it a few months back....
It is it again !!!!
Need to replace the plug as well. The plastic has become brittle.



Thanks a lot

Marco

Marco (or anyone else) !

Do you remember the part number for the plug? I had the same problem - the MFTS seems to be the cause of my no-boost. Unplugging it has returned the car to normal. The plastic is very brittle and slightly disintegrated. I will replace the MFTS, but I need to replace the plug also -

Anyoine with a part number for the plug - much appreciated!

Jason

[rotoryboy]

Iirc