Can someone tell me what the air intake vacuum switch valve does? Car is a 2002 Toyota Corolla. One of the hoses was broken off the vsv. Engine started running rough, we also have an evap system error code. Could this be the cause of both?

VSV is in the lower middle of the picture near the green tag.

In a nutshell... YES. The EVAP code is from the vacum line being broke. The rough running is from the broken hose also.

On command from the PCM, the VSV causes engine vacuum to suck in, to be burned in the combustion chambers, fuel vapors from the tank. One end is hooked to intake vacuum. If it breaks you will get a vacuum leak and an EVAP system code (probably P0442).

Thanks, guys, for the help. I've got a replacement part on order.