It stands for Technical Service Bulletin. A TSB is a manufacturer’s recommended procedure for repairing a problem that has affect many vehicles. It indicates that it is a common problem regardless of lemon law in California.
“TSB” is usually followed by a series of numbers. For example, TSB SIB-32-04-07 was issued June 1, 2010 and it applies applies to Model Year 2011 BMW 328 cars. It provides a new technical process for BMW dealerships to identify causes of steering complaints.
It is not unusual for more than one TSB to apply to a car.