Unidentified Sensor? Switch?

[Eggio18]

Hello to all fellow 8L enthusiasts, I'm new to this forum. Just a quick intro, I'm from Hong Kong, owner of a S3 8L (AMK) RHD brought half a year ago from a guy who doesn't maintain the car much. Took me a while to get it going happy again, absolutely loving it.

Yesterday when checking the PCVs, I found a sensor / switch hanging around unconnected (circle in red), it is located lower left of the engine bay, down between the alternator and radiator fans.
The sensor / switch had a orange plastic seal in it.

The only thing I can find there that can plug this in to, is a upright metal tube extend from below.

Anyone can suggest of what this Sensor / Switch is for?

(sorry for the blur).

 

[S3 Hilife]

It's hard to tell from those pics but with the location it could be the elctrical plug for the over-run pump which can be partly seen in your lower pic (cylindrical shape) or the plug that goes on the top of the ac compressor (pressure switch or something)


Steve

 

[<tuffty/>]

Power steering pressure switch...

I believe its used by the ECU to help with load control at idle while you are low speed manoeuvring

<tuffty/>

 

[S3 Hilife]

There you go

 

[Eggio18]

Thank you Steve and Tuffty.

 

[VAG-Slag]

The wire to mine was severed a long time ago... Doesn't seem to have made any difference

 

[<tuffty/>]

Its used for idle stabilisation... when at a stand still and you turn lock to lock the extra load of the pump adds load to the engine which can potentially stall the engine out... the ECU monitors the pumps pressure with this sensor to ensure there is enough load resource available for when the engine rpm starts to drop off...

If its working then idle should remain stable when on full lock... if not then idle can dip a bit before the ECU catches up and stabilises again... worse case is the engine can stall... depends on the circumstances...

<tuffty/>

 

[Eggio18]

The wire to mine was severed a long time ago... Doesn't seem to have made any difference

Thanks mate
Happy to know that it doesn't have much effect when not connected, as i just found out the switch doesn't seems to click in. In that case, i'll leave it out hang a side

 

[Eggio18]

Its used for idle stabilisation... when at a stand still and you turn lock to lock the extra load of the pump adds load to the engine which can potentially stall the engine out... the ECU monitors the pumps pressure with this sensor to ensure there is enough load resource available for when the engine rpm starts to drop off...

If its working then idle should remain stable when on full lock... if not then idle can dip a bit before the ECU catches up and stabilises again... worse case is the engine can stall... depends on the circumstances...

<tuffty/>

Thanks for explaining in detail Tuffty.
Just compare mine to the photo of a same switch, at first I was thinking why it look so different, then I realized that my switch's head is stuck together with the wired connector, while the so call switch is now a empty hole with fluid in it.