Utah Code § 77-18-117: Fine not paid -- Commitment.

(1) When a defendant is sentenced to pay a fine in addition to a jail or a prison sentence and the judgment is that the jail or prison sentence be suspended upon payment of the fine, the service of the jail or prison sentence shall satisfy the judgment.

(2) If a defendant fails to pay the fine and the court finds that the defendant failed to make a good faith effort to pay the fine, the court may, after a hearing, order the execution of the suspended jail or prison sentence.

(3) If a defendant is sentenced to pay a fine only, or is sentenced to jail or prison and a fine, with neither suspended, the defendant may not later be committed to jail for failure to pay the fine.