Is there a policy or procedure to award an MOS based on civilian education (example: diesel certification for 91B)?

There is the ACASP (Army Civilian Aquired Skills Program)
http://www.army-portal.com/jobs/acasp.html

I was in recruiting command for 14 years and enlisted several under ACASP, Army Civilian Acquired Skills Program. Details can be found in AR 601-210 and DA PAM 611-21(MOS specific requirements). Some will allow for "skipping" all of AIT or portions of AIT. Depends on the MOS. Usually, there is an education, certification, experience in civilian job or a combination. 91B is one of the MOS's but there are too many in the program for me to list all of them. Most are vocational trade type jobs and the rest are in the medical field.

Thanks again for the responses. I found the info I needed to pass on to the Soldier.

I built houses with my father for years before I attending AIT for carpentry/masonary specialist, but back then we still had to train on demolition and land mines, they don't do that anymore so I would have breezed thru the construction portion now. I actually knew things the instructors did not know, so I got to enlighten them on a few aspects.

Yes sir, it is called the Army Civilian Acquired Skills Program (ACASP). AR 601-210 covers it. This applies to new recruits enlisting. There are specific requirements for each MOS that is applicable. 91B is one. Most require a combination of formal training from an accredited institution plus job experience, some just the training. In most cases, they do not attend AIT but have to go through a certification procedure. Depends on MOS, but advanced pay grades do apply. Ie, enter as E3 and automatic advancement to E4 after certification. You can find more info on ACASP at goarmy.com

There used to a program referred to as Civilian Acquired Skills. As I recall for the NG there was a NG regulation that explained the process. What we did with a soldier is they brought in their Work History, education, and what other supporting documents. Submitted a 4187, requesting the soldier pick up MOS X, as a secondary MOS. Then once Awarded we put them in the slot that was vacant with the newly reassigned MOS and made that the primary.

91-B used to be medics...

I knew a few that traded what was then called "Skills for Stripes." If they came in with a certain set of skills and all the certs to go with a particular MOS, then all they had to do was Basic and call it good. A welder in my Engineer unit (58th CEC) that did that, along with a medic I knew in Germany.

There will always be an aspect of the job that is specifically military, so it would be very difficult to award an MOS strictly on civilian experience and education, with no knowledge of the military part.

In general NO, but there have been programs for a specific career field like Medical Doctor that can allow the civilian training and certs to accepted in lieu of training while in the military already when need far outpaced availability. Id bet something like pilots of the off the shelf commercial AC used by military would be another likley possibility of a direct commission and award of a career field. and it would not surprise me to find out there was a like program when needed for an obscure enlisted MOS that allowed a civilian training to be used in place of the military equivalent...but I dont know of one specifically.
Construction trades would be a likley candidate for that as operating a backhoe is the same no matter what the uniform you're wearing, same as swinging framing hammer or operating a skill saw. But again in the modern army im not aware of any opportunities.
Recruiters, what say you? This is your lane