ECM Table Operation

The ECM analyzes signals sent from various input sensors and operates systems to control emissions and engine performance. ECM has 2 parts: controller, and Programmable Read Only Memory (PROM), which fits inside controller.

PROM contains factory programmed information including specific engine calibration data, transmission axle ratio, vehicle weight and other important data. Although a controller may be used for many different vehicles, PROM may not because of its specific data.