What happens is I fail a drug test on pretrial probation?

You may be kicked out of the diversion program that it sounds like you were enrolled in. If you had a lawyer when you entered Pretrial diversion I suggest you contact that lawyer immediately. I have had this situation come up many times and have been able to keep my clients in Pretrial diversion by showing that the marijuana use has stopped and that the marijuana in the test was from prior usage. Noah H. Pines

Mr. Pines gave some good advice. I just want to add that if you are kicked out of the pre-trial program then your case will be referred back for prosecution. You probably want to stay in your pre-trial program if possible so contact your original lawyer or a new one to try and accomplish this goal.

It will be up to your probation officer, but most likely they will kick you out of pretrial diversion. What this means is that your case will go back on an arraignment calendar (if you didn't enter a not-guilty plea previously) or be put on a trial calendar. You need to speak with your probation officer and find out what is going to happen. Diversion is a big benefit to you because it lets you get off probation quickly and avoid a conviction. You usually even have the option of getting the arrest expunged from your record. You should make the best case you can for staying on diversion and finishing. If you aren't allowed to stay on diversion, there may still be ways to avoid having a conviction on your record by using the conditional discharge provision in the law. You will want to speak with a knowledgeable attorney quickly if they kick you out of diversion. Of course, your long term issues will become much more manageable if you quit smoking pot.