OEM (Original Equipment Manufacturer) Factory manuals are written by the company that manufactured the vehicle. Aftermarket manuals are not. Although some factory manuals are intended for the DIY novice mechanic, the great majority are written with the service technician or experienced mechanic in mind. OEM Factory manuals are written with the assumption that you have a certain degree of knowledge and familiarity with the brand, and it is not uncommon for a factory manual to call for a specific tool by manufacturer part number, for example.
Technicalities notwithstanding, a factory manual may be the most comprehensive publication available for your vehicle whereas an aftermarket manual focuses on explaining service, repair and maintenance steps in a super detailed stepwise manner to help novice mechanics.
To learn more in depth details about the difference, here's a great article we wrote explaining OEM Service Manuals vs DIY Aftermarket Service Manuals in detail.
In a nutshell, none. Although at one point, repair and service manuals, by definition, were somewhat different (e.g. a repair manual provided actual repair information, whereas a service manual provided basic maintenance and service details). Presently, the differences have disappeared and the information presented is one and the same. So, whether you call it a repair manual, a service guide, or a shop manual, they all provide repair, maintenance, and service details.
One caveat worth noting is that although the word "repair" stands for fixing something, do not expect a manual to tell you how to repair every system per se. In this day and age of re-manufactured parts, it makes more sense time- and money-wise to simply exchange or buy new parts instead of repairing them.
I think we've pretty much heard all possible variations on ways to describe a repair manual, which is the name of choice here at The Motor Bookstore, although we also call them just "manuals," for short. Anyway, here's the list we've compiled just in case you want to make sure we're talking about the same thing.
- Service manual
- Workshop manual
- Shop manual
- Maintenance manual
- Owner's manual (see below)
Note: We've also seen the word "manual" misspelled as "Manuel," which really is a Spanish name. Gracias.
An owner's manual is the booklet that comes with new vehicles, usually found in the glovebox.
An owner's manual contains instructions on how to operate vehicle accessories, tire information, recommended maintenance intervals, types of lubricants required, a dealer directory, etc. But that's it. An owner's manual will not provide information on how to service or fix your vehicle, perform an oil change, tune-up, or anything of the sort. For that kind of info you will need a repair manual.
A DIY (Do-It-Yourself) manual is written with the consumer in mind, and therefore publishers make every effort to present the information in an easy-to-understand format with lots of actual photos and illustrations depicting step-by-step procedures.
On the other hand a professional repair manual is written with the technician or mechanic in mind. This means that a certain degree of mechanical knowledge is assumed and, therefore, instructions may not be as clear to the weekend do-it-yourselfer novice mechanic. Additionally, professional manuals usually cover a wide range of makes and models which makes them big (sometimes into the thousands of pages) and, consequently, more expensive.