That is the code for incorrect resistance on the seatbelt pretensioner circuit (code 46 driver side, code 47 passenger side). It is a common problem and is usually caused by a poor connection under the seat. Turn off the ignition, open the connector, clean the pins and reassemble. Applying dielectric grease to the pins should make the repair last longer. In rare cases, the connector might need to be replaced.
It is a good idea to avoid storing things under the seats because contact with the connectors can sometimes trigger the problem.
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles
2003 XLT 2.3L M5OD-R1 reg cab beater, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid