If you are unable to come up with the funds to pay the balance due on your 401K loan the IRS will consider it a distribution subject to income taxes and possibly penalties.
If you are unable to repay, it becomes an early distribution of your retirement plan subject to income taxes and early distribution penalties. If it is possible to repay any of it, it would be a good idea.
Since this is your money the company will just reduce the amount you would have received when you eventually leave the company or sooner if that is their policy