Not true. You need reasonable suspicion to stop a vehicle. Then you can ask for a license and registration. Vehicle can’t be searched without probable cause, even if a vehicle search qualifies as an exigent circumstance.
Normally they have to direct you to a police station and wait for a judge to issue a warrant.
Cops don’t need a “reason”. OK, at least not a “reasonable reason”. You could be Jesus Christ, pure as pure can be, and you can get pulled over. Spoiler alert: Police lie....because, they can.