gearbox sensor

Hi Guys, I am in serious need of help. There is cable connected to the coolant control valve (I believe) the cable is connected direct to the gearbox but I am unable to know the exact name for this full cable or official Audi part number please see images below. I wish I could actually give...

had some gearbox malfunction messages come up on the dash intermittently and in one case my car stalled ( its an automatic!) 2.0Tfsi Took the car to audi garage where i bought and always had serviced by them and they tell me its going to cost 2k for a sensor in the gearbox because they need to...