I recently came across the usage is andar to mean to function. I attempted to use this in a Mexican context where I didn't want to eat, and attempted to say "My mouth isn't working right now" as "Ya no anda mi boca". This got a good few laughs, and I was corrected to use "funcionar" in place of "andar".
So my question, what is the subtle difference between the two when talking about if something is working or not in this context? Why can I say " No anda mi moto" but not "boca"?