Legal Question in Criminal Law in California

Sorry, but the answer is maybe.

In order to be able to search without a warrant, they must have probable cause to search. Essentially, they must have sufficient information to believe the item they're looking for is in the place they want to search.

It will matter what they say they smelled, why they were contacting you in the first place and the connection to your car.

It sounds like you were stopped for some sort of DUI investigation and then asked to do field sobriety tests. They may have had a legal reason to search - but they may not have. It will take a review of the police reports in your case to tell you for sure. The courts have limited their ability to search cars when people aren't in them, but in a DUI investigation if they smelled marijuana, they *may* have been entitled to search.

There's just no clear cut answer without reading the reports. You'll need to consult with a criminal defense attorney in a face-to-face consultation for a definitive answer.