Check Engine Light (amongst other things)

[ARE]

Hey all,

I'll try to be brief with this, we're all busy people. I own an 11 reg Abarth (Essesse version) and have done for four years now. Serviced regularly, throttled occasionally, loved always. After a full service and MOT approx. a month ago, I'm coming up a relatively steep incline at somewhat high revs yesterday and after upshifting from 4th to 5th, get a check engine warning. After shitting myself and turning the radio off, I come to the conclusion I'm still driving okay and being only a couple of miles from home (mostly downhill) I ease her gently back and don't notice any issues in terms of the drive.

Being the wannabe mechanic I am, I have a quick gander under the bonnet when home and - to my confusion - notice this entire pipe and whatever connects to this pipe is missing (please see picture, obviously not of my own intact engine bay). My first questions are these, what exactly is this part I'm missing, and what are the chances it's come away of its own accord? I had my car into the garage that have been the only people to service/MOT it for the past year today and the owner gave nothing away if there was any possibility the responsibility of the missing pipe was theirs. I did have some absolute moron reverse into me a couple of weeks back and shunt my car forward 3-4 feet but the damage, seemingly, was only superficial. One last question for this paragraph, what kind of damage have I risked by driving around without it in the first place?

Having spoken to the garage again since dropping my car, they've said the fault code was for the actuator being stuck open. My brief research leads me to believe these two issues probably aren't related but I come to you more knowledgeable individuals with this already overly-detailed post to clarify if the two may be connected. I would also be extremely grateful if anyone is able to give me a rough idea of just how hard my wage this month will be hit. Any additional advice, comment or slander is also welcome.

Cheers for reading.