If a debtor is behind in house or car payments, can Chapter 13 stop a foreclosure or repossession from taking place?

Yes, in most cases. Unlike Chapter 7, where the debtor can usually stop a foreclosure or repossession only if the creditor agrees to a reaffirmation, a debtor in Chapter 13 may provide for car and mortgage payments in the Chapter 13 plan, and the creditor may be required to accept these payments instead of proceeding with foreclosure or repossession.