Legal Question in Criminal Law in California

You mention there was "no probable (reasonable) cause" to pull the car over ... that's an opinion, it is not a fact. The officer will have a different opinion - that much is guaranteed. The reason/s alleged for the stop and search will be written in the police report.

I suggest consulting a local criminal defense attorney who routinely practices in the court in which your boyfriend's case will be heard. I think every attorney will agree, they have not seen a report written which says, "I pulled over the car for no reason."

There was some reason ... what is was in reality and what will be alleged may be two different matters. Either way, whether it was a "good" one or not can only be answered by the attorney handling the case. Good luck!

You should look at the police report. A police officer can't just pull someone over on a "whim". You might have a case and should consult a local attorney that specializes in criminal law and traffic violations in particular. A police officer must have a reasonable suspicion that criminal activity is afoot to pull you over.