I bought my wrx about 2-3 months ago and ever since I bought it I haven’t been able to switch si-drive modes i have a cvt transmission and all i hear is a error sound or some type of sound indicating I couldn’t switch
You need to add some details to get help. Model year, trim, modifications, error codes on dash, etc. A good starting point is to get codes read at some auto parts store. Advance auto, autozone n a few other places do it for free.
If you bought it used, don't assume car is stock just cause dealer said so.