http://www.nhtsa.gov/cars/rules/impo...da10102012.pdf
Mazda Canada gave me letter saying my car met all epa and dot standards except FMVSS 138, and the border guard said I can't import it because of that issue (quote from my letter):
1. FMVSS 138 – Tire Pressure Monitoring System (TPMS Requirement)
As a result, Mazda Canada Inc. is unable to certify this vehicle’s compliance with all applicable U.S. safety requirements...