None of the NAFTA countries may assess customs duties on goods that are exported for repair or alteration in another NAFTA country pursuant to a warranty and then re-imported. This is true regardless of the origin of the goods and regardless of whether the goods could have been repaired or altered in the exporting country.
A NAFTA country may, however, choose to assess customs duties on the value of the repairs or alterations performed in another NAFTA country that are not pursuant to a warranty. The rate of duty applied is the preferential NAFTA rate, regardless whether the goods repaired or altered are originating. Canada will assess duties on the value of such repairs or alterations performed in Mexico and the United States using the rate of duty applicable under the Canada-United States Free Trade Agreement, as incorporated into Annex 307.1 of the NAFTA, for goods from both countries. Mexico will not assess duties on repairs or alterations performed in the United States or Canada. The United States will not assess duties on repairs or alterations performed in Mexico, not pursuant to a warranty, but will assess duties on those performed in Canada.