Justin Bieber -- Driving Without a License

Justin Bieber's precious Fisker Karma sports car has been violated ... 'cause the back license plate is MISSING and the culprit is still at large ... according to law enforcement sources.

We're told J.B.'s property manager noticed the missing plate last night while working at the Bieb's Calabasas mansion.

Fully realizing the seriousness of the offense, the manager called the L.A. County Sheriff's Department ... which shockingly came out and took a report.

It's unclear if the missing plate was stolen or just fell off. This could mean the Biebs will temporarily have to sideline his paparazzi magnet ... because it's illegal to drive without a back plate.