The Cummins M11 was an inline six cylinder, 10.6 litre diesel engine. It was introduced in late 1993 and replaced the Cummins L10. The M11 was used in transit buses as well as motorcoaches.
In 1996, Cummins made changes to the engine and added their CELECT Plus electronic control system to improve fuel efficiency, performance, and reliability. This was called the M11 Plus or M11E. This engine also met the 1998 EPA and CARB emissions standards.
Cummins updated the engine in 1999 with new accessories and electronics under their Interact System. The M11 became known as the Cummins ISM.