Can I reinstate my MC without paying outstanding civil penalties?
Generally no. A carrier that doesn't pay a final civil penalty, or keep to an agreed payment plan, can be prohibited from operating and have its registration suspended or revoked (49 CFR 386.83). If unpaid penalties caused the revocation, they need to be paid or resolved with FMCSA before reinstatement for that cause can go through.
Civil penalties assessed under 49 U.S.C. 521(b) are debts owed to the federal government. Under 49 CFR 386.83, unpaid final penalties can lead to an operating prohibition and suspension or revocation of registration, and the registration isn't restored until the penalty is paid or resolved.
Payment instructions are in FMCSA's penalty notice. Once FMCSA's records show the penalty paid, your reinstatement is submitted to FMCSA promptly; FMCSA controls the timing.
Where a lump-sum payment isn't practical, carriers can ask FMCSA about a payment plan. The arrangement needs to be agreed with FMCSA, not just proposed, before reinstatement can proceed.
Penalties can be contested through FMCSA's administrative process under 49 CFR Part 386; that is a separate process from reinstatement. Whether to pay or contest depends on the amount and the merits, and a transportation attorney can advise.