MFTS function and substitution

[UrS4boy]

Is the signal the dash the same as the signal to the ecu?

No, it's not the same. The ECU uses a separate temperature sender, the G62 Coolant Temp sensor:

http://forums.quattroworld.com/s4s6/msgs/20985.phtml

[UrS4boy]

Sure but don't forget the car was built for many, many markets ....Consequently in some geographical locations not all features are really that relevant for us seasoned and careful owners, this high temp boost cut being on of them (IMHO)

Sure.

It has been suggested to me that Audi was more worried about the small bodied B3/B4 cars with the side-mount radiators and less airflow to cool the radiators than the C4 bodied UrS cars. The 200 20vT also had the side mount radiators with the 3B also. Hence, the MFTS did different things for the 3B, ABY and ADU than the AAN with its larger front-mounted C4 radiator.

I never said don't do it. I just suggested that I didn't think it was a smart idea (to eliminate a factory safety feature) for the sake of a few GBPs.

[prj]

ECU will kill your boost via G62 anyway if you let it go high enough.

I don't know why the MFTS was used, but it's not used on S4 and S6.

[andy10v]

No, it's not the same. The ECU uses a separate temperature sender, the G62 Coolant Temp sensor:

http://forums.quattroworld.com/s4s6/msgs/20985.phtml

Sorry, I should have mentioned 3B.

[Rusty]

So in conclusion, on an ABY, the MFTS gives dash temp signal and over temp boost cut at temps over 120degC only. Correct?

[UrS4boy]

So in conclusion, on an ABY, the MFTS gives dash temp signal and over temp boost cut at temps over 120degC only. Correct?

Yes. And they are available for much less than 120 GBP. Try this link:

http://www.ebay.co.uk/itm/Behr-Water...item53fb179af5

"The F76 Multifunction temperature sender has different functions in the ABY and ADU than the AAN. For all three, the MFTS is the sender for the temperature gauge in the instrument cluster. On the ABY/ADU, the MFTS is also connected to the ECU via pin 46 of the T55 ECU connector. Using this pin as a high temp alarm (> 119 C) - the ECU cuts off active boost control as a safety measure. However, for the AAN, pin 46 is not used, as indicated in this Motronic 20VT AAN pin-out. On the AAN, the MFTS F76/R pin connects to is the HVAC/climate system to shut off the compressor during such high temperatures."

http://forums.quattroworld.com/s4s6/msgs/22584.phtml

[Rusty]

Just thinking that a switch be used to ground the MFTS alarm pin and act as a valet mode in case of giving the car to a garage or unfamiliar driver etc. Might be less obvious than removing the n75 plug.

[Error404]

you leave your car with garages or unfamiliar drivers?

[Rusty]

Not in living memory just a thought

[twoqu]

Just thinking that a switch be used to ground the MFTS alarm pin and act as a valet mode in case of giving the car to a garage or unfamiliar driver etc. Might be less obvious than removing the n75 plug.

What, like this:

http://www.s2forum.com/forum/showthread.php?t=24254

[Rikki Kitto]

Thought the MFTS cut the rad fan in at 90 also?

[Rusty]

Cheers Robin, great minds and all that

MFTS does not do anything with the fan, that's all down to the fan switch on the radiator.

[afterburner]

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[UrS4boy]

What, like this:
http://www.s2forum.com/forum/showthread.php?t=24254

But make sure you read to the end of the thread, not just the first post.

Gee, I see it was me who suggested the Valet Mode. Hmmm...the mind, she forgets as the little grey cells go on extended holiday, Miss Lemon.

[Rusty]

Paul's thread idea was to link the two pins and it was this that failed.