Yes, but falsity of the intellect is concerned essentially only with the judgment of the intellect because the intellect cannot be false in its knowledge of simple essences (since this is either true, or it understands nothing at all).
Falsity can exist in the intellect because the intellect is conscious of that knowledge, as it is conscious of truth -- whereas in sense falsity does not exist as known (Q17 A2).
As the sense is directly informed by the likeness of its proper object, so is the intellect by the likeness of the essence of a thing. Hence the intellect is not deceived about the essence of a thing, as neither the sense about its proper object (Q17 A2).
But in judgment (i.e., when affirming and denying), the intellect may be deceived, by attributing (to the thing of which it understands the essence) something which is not consequent upon it, or is opposed to it.
Because the essence of a thing is the proper object of the intellect, we are properly said to understand a thing when we reduce it to its essence, and judge of it thereby (as takes place in demonstrations in which there is no falsity).
The intellect is always right as regards first principles, since it is not deceived about them for the same reason that it is not deceived about what a thing is. For self-known principles are such as are known as soon as the terms are understood, from the fact that the predicate is contained in the definition of the subject.