Can a police search the passenger of the car?

If they have reasonable suspicion that an offense, is being, was being, or is about, to occur -OR- for their safety.

Yes an officer can still search your car. The officer could claim there is probable cause to search your car, because you just denied the search, which the officer would say, looks like a sign of...

with a warrant they can check anything.

anytime they want but you have a right to not let them until they have a warent to search your car and they might take the car but that's all they can do so make sure you don't have anything and if u...

The police in many countries do not need a warrant to do a vehicle search. Probable cause is enough to do a roadside search and that could be a bottle rolling on the backseat floor, the smell of...