here got this from one of our manuals
Total Loss Coverage (TLC) is insurance protection that covers the
difference between the borrower’s insurance settlement for physical
damage and the net payoff of the automobile loan.
Without TLC (aka: GAP insurance), the borrower will be responsible for
paying the difference between the actual cash value (ACV), less the
physical damage deductible and the loan balance out of pocket. This
gap occurs most frequently within the first three years of the loan term.