The mapping contains all the data necessary for the operation of the engine. It is divided into tables, each of which contains the information of all the sensors and electrical devices connected to it; coils, injectors, temperature sensors, pressure sensors, crankshaft position sensors, battery voltage, etc. The tables are stored inside the electronic control unit.

The essential purpose of a remapping is to improve the performance of the engine, especially in the case of modifications to the exhaust and / or intake system, or to the engine. In this case it is necessary to intervene on the tables of injection times and ignition advance.