A few things that you need to be aware of:
(1) There is no true expungement in California, it only serves as a dismissal. Therefore it will show that conviction for your DUI as being set aside.
(2) It will never be removed from your DMV record even if a 1203.4 dismissal is granted.
(3) You need to either (a) wait for your probation to be terminated, because most probably you were placed on 3 years of probation or (b) apply for early termination of probation and if granted apply for the expungment.
Speak to an attorney about your case before making a decision on how to move forward.
Elliot Zarabi www.FreeCriminalConsultation.com 213-612-7720 This answer does not constitute full legal advise. I do not know the full details of the case and therefore cannot make a full determination on your case or your answer. I always recommend speaking to an attorney in detail regarding your case.
You may be able to apply for an early termination of probation and an expungement based on your particular set of circumstances . You may wish to consult with an attorney to discuss this in more detail as well as discuss the difference between sealing and expungement.
Sorry to break the bad news, but a DUI stays on your records for 10 years. In California, there is no true "expungement" unless the charges were dismissed or your were acquitted. The best you can do is get a dismissal after completion of your probation pursuant to PC 1203.4. You cannot get your record sealed or records destroyed. The DUi shows up as a conviction and then a dismissal. You can try to get a 1203.4 dismissal before your probation is finished, but most judges will not do so since it is discretionary on their part. For the near term, you'll need to look for something other than a truck driving job.
The information and legal suggestions made herein do not in any way create an attorney-client relationship. The responses provided herein discuss general principles of law and should not be relied upon by the asker in making legal decisions. Only an attorney who has met with the asker and fully reviewed the facts and circumstances of the asker's individual case should be relied upon for legal advice. If you find my suggestions helpful, please mark the appropriate box as helpful.
To somewhat echo and expand on the previous answers...
Even if your 1203.4 dismissal (commonly and incorrectly referred to as an expungement), it has zero effect on your DMV history.
You cannot "seal" an adult record and there is no way to prevent this conviction from showing up at some level on your criminal history and for at least 10 years on your DMV printout.
The above answer is for general information only and is based on the information you posted. Every case is fact dependent, so to get a thorough analysis of your situation, you will need to consult face to face with an attorney licensed to practice in the jurisdiction where the incident took place. Do not conclusively rely on any information posted online when deciding what to do about your case.