What is this sensor?

[electronmirror]

C5 2010 Exclusive Tourer 2.0 HDI 163 (engine code RHH)

Can someone enlighten me as to the function of the circled sensor?
There is no cable/connector plugged into it and pretty sure there never has been since i bought the car middle of last year.
Oddly there is a short cable just to the left of the sensor tucked out of the way that has a connector which does not fit into the sensor. It has a blanking plug fitted in the end of the connector which looks like a factory original. All very perculiar

What does it do and what is the effect of it not being connected?
Seems to run fine and returns slightly better fuel consumption than my Xantia which is now back in service while the steering rack on the C5 is being replaced

[RichardW]

Not a sensor, think it's an air flap in the mixer unit to control the bypass on the intercooler and help with temperature for regen. See viewtopic.php?t=62155&start=19 Surprised there is no fault with it not plugged in, unless the DPF has been, er, tampered with!!

[GiveMeABreak]

It's the air mixer assembly, - see my specific post here on the thread that Richard linked to - it seems that it wasn't supposed to be connected - but they didn't bother updating the information.

[electronmirror]

Richard, Marc,

Many thanks for the comments and link back to Marc’s old post about the unused connection to this air mixer assembly.

Point taken about Citroen failing to update info on this redundant connector, it is a French manufacturer/car after all

Ted