A police officer pulls you over for a broken taillight. While talking to you, he tells you to get out of the car and performs a search without a warrant. The officer finds drugs in the car and arrests you.
What the police claim is that they had probable cause for that search since you had a broken light. Is this true?
It is not. They do need probable cause to carry out a warrantless search, but they cannot use minor traffic violations. It's simply not enough. They need some other evidence that supports their belief that you have drugs in the car. They have to show in court that they had a reason for the search.
If they can't do it, then the only way to perform a search is to get a warrant or to get your permission. Without those, the search is often illegal, and they can't use the evidence they gather during the case.
Now, the broken taillight is a valid reason for a traffic stop. They did not break the law by pulling you over, and many officers look for these types of excuses when they want to find out if a driver is under the influence. That's fine. But just because they can pull you over does not automatically mean that they can search your car without something a bit more concrete.
Do you think that the police carried out an illegal search? If they did, it could have a massive impact on your case, so make sure you know exactly what legal options you have.