Does anyone know what this is, and what it does? Thanks in advance!

 

Welcome to the forum

IAC Valve, idle air control valve, found on all fuel injected gasoline engines

Fuel injected engines don't have Jets to control fuel flow at idle, so idle screws won't work, and there is no Choke Plate for cold engine operation, because no Jets
So the computer needs a way to set the idle level for cold engine and warm engine
The IAC Valve is on a passage that by-passes the throttle plate, so computer can raise and lower idle RPMs by opening and closing the valve and adjust air/fuel mix accordingly

Its a 12volt solenoid, it gets 12volts with key on, red wire, the computer "pulses" the other wire(ground wire) to open and close the solenoid/valve

These can be removed and cleaned