The box has the FCC ID# on it... as long as those match, it will work:
http://car-part.com/cgi-bin/search.cgi
(I searched for "Theft/Locking, keyless entry (behind dash, LH fuse box)")
2003
Chassis Control Box(not Engine)
Nissan Pathfinder 285955W500 2310 $75 Glenn and Jerry's USA-TX(Fort-Worth) Request_Quote 1-888-251-6115 Request_Insurance_Quote
2003
Chassis Control Box(not Engine)
Nissan Pathfinder PN # 285955W500 A FE3744 $Call Frank's Auto & Truck Parts USA-TX(Brownsville) E-mail 1-800-882-4349
2002
Chassis Control Box(not Engine)
Nissan Pathfinder $Call Adam's Auto Sales & Parts USA-TX(Houston) Request_Quote 281-575-7278 / 281-575-7846 Request_Insurance_Quote