The trip computer (Outside temp, DTE, MPG, etc but NO tire pressures) is only available as part of the Premium Package. Do you have this option?
From Nissan USA:
# High Intensity Discharge (HID) xenon headlights with manual headlight levelizer# Intelligent Key keyless entry and ignition system
# Bluetooth® Hands-free Phone System# Xtronic CVT™ with manual shift mode including steering wheel-mounted paddle shifters
# Tow hitch pre-wiring
# Fog lights
# Digital Bose® audio system with AM/FM/in-dash 6-CD changer Eight speakers, including Nd® Richbass® woofer# MP3/WMA CD playback capability# Radio Data System (RDS)
# XM® Satellite Radio¹
# Speed-sensitive audio volume
# Steering wheel-mounted audio controls
# Drive computer (mpg, distance to empty, average speed and elapsed time)
# Outside temperature display
# Fold-down front passenger seat
# Driver seatback pocket# Center console with dual-level storage tray
# Dual illuminated visor vanity mirrors
# Interior accent lights
# Luggage side hooks (two)
# Retractable cargo cover
# Rear foldable cargo organizer