A2L is a file format used for storing data utilized by gas engine electronic control units (ECU). A2L file stores information need by ECU to control parameters of various parts it supervises.

A2L format was developed by ASAM MCD-2MC (ASAP2) workgroup. Data used by ECUs can be managed using ASAP2 Tool-Set software package. A2L databases are controlled by ASAP2 Studio software program. A2L files can be used for testing and calibrating ECUs.