AV Tikkun - Sense: Hearing
"To hear" in Hebrew means "to understand," to fully integrate into one's consciousness (into one's heart, not only to understand intellectually in one's mind). To hear another is to fully understand his dilemma and emphasize with him. In the beginning of Isaiah (read on the Shabbat before the 9th of Av), it says: "if you desire [tovu, from the word Av] and hear [the sense of Av], you shall partake of the goodness of the land." The sense of hearing is the sense of inner balance, the foundation of rectified existence. (Imbalance is the source of all fall and destruction). A well balanced ear, a well oriented sense of hearing, possesses the ability to discern and distinguish in everything one hears truth from falseness, as is said (Job 12:11 and 34:3): "the ear discerns words" ozen malin tivchan (the initial letters of this phrase spell emet--"truth").
ELUL Tikkun - Sense: Action
The sense of action is the "sense" and inner "knowledge" that through devoted deeds of goodness (tzedaka and chessed) one is always able to rectify any blemished or broken state of the soul. This is the sense necessary for the spiritual service of Elul, the service of repentance and true teshuvah to G-d. The sense of action is thus the sense never to despair.