Can I be conviced of a DUI for MJ even if I have my cannabis script?

A cannabis club card does not give you permission to drive under the influence.

Can I be convicted? Of course. Nobody told you that having your card allowed you to? Drive Under the Influence? of alcohol or other drugs, which is they way the law reads. You could be charged if driving under the influence of cough syrup or prescription meds too. It is the impaired driving that is illegal, not the substance used that is important in DUI. A little free advice: If arrested for DUI, whether alcohol or drugs, then upon release from jail or booking the defendant is given documents that include a notice that you have only ten days to file a request with DMV for a hearing on an appeal of the automatic suspension of your license imposed by DMV upon your arrest. That is separate and runs consecutively with any suspension that may be imposed by the DMV, or the court upon conviction. Contact DMV and do so, timely if you think you have grounds for appeal, then appear at the scheduled DMV appeal hearing and present your supporting evidence and witness testimony. If you don't know how to do these things effectively, then hire an attorney that does. When questioned, arrested or charged with any crime, the proper questions are, can any evidence obtained in a test, search or statement be used against you, can you be convicted, and what can you do? Raise all appropriate defenses with whatever witnesses, evidence and sympathies are available for legal arguments, for evidence suppression or other motions, or for trial. While this isn't a 'capital case', you certainly face fines and potential jail, so handle it right. No amount of free 'tips and hints' from here or elsewhere are going to effectively help in a legal defense. If you don't know how to represent yourself effectively against an experienced prosecutor intending to convict, then hire an attorney who does, who will try to get a dismissal, charge reduction, diversion, program, or other decent outcome through motions, plea bargain, or take it to trial if appropriate.

How do you fight it? You get a lawyer. Yes, they can still charge you with driving under the influence, even with a medical card. That card allows you to possess and use, but not to drive under the influence. The key is "under the influence". Can they prove this? Only your attorney can answer that after reviewing the entire case. There is no "legal limit" for THC, so they can't rely on a lab report with a number - they have to prove you were unable to drive like a sober person. There may also be a motion to suppress the evidence if they didn't have a legitimate reason to stop you in the first place. You've got to get an attorney.

Your question requires an attorney consultation. It is not a simple question that can be answered on this type of forum. There are many factors that would need to be considered and evaluated. However, the short answer is yes, since a DUI entails not only alcohol, but drugs as well. I strongly suggest that you contact an experienced criminal law attorney for a face-to-face consultation and give him/her all of the facts surrounding your arrest. He/she would then be in a better position to analyze your case and advise you of your options.