General Motors' technical service bulletins generally contain information about many different non-safety issues that can emerge after a vehicle leaves the factory. A typical GM service bulletin contains the bulletin number and date; the system to which the bulletin applies; makes, models and years of the cars affected; a description of the problem; and any known solutions and part numbers that apply.
Technical service bulletins focus on non-safety related problems that might affect vehicle performance or longevity. Parts that fail prematurely or that don't operate as they were supposed to are often the subjects of such bulletins. Technical service bulletins advise service technicians about diagnostic procedures as well repair procedures, as well as any pre-authorization procedures necessary to begin repairs. A technical service bulletins may specify the tools, techniques and required parts needed to address a problem. Technical service bulletins can alert service technicians and dealers to other issues such as changes to tire or cooing system pressure, lubricants, or other maintenance requirements.
Technical service bulletins are not recalls and do not necessarily give customers free repairs, but can indicate that the manufacturer is extending warranty coverage for specific issues for the vehicles specified. Because a vehicle is listed by make, model, year or VIN number doesn't mean every vehicle has or is likely to develop the problem. Often, the problem is only diagnosed in a small number of cars from the production run or in those operated in certain areas under certain conditions.