Cummins Diesel Engine EPA21 6.7 liter ISB/QSB Engines Module. The Cummins 5669858 Diesel Engine Module is a direct replacement part made of ABS and aluminum. It is designed specifically for diesel fuel type and is an authentic Cummins brand product. The engine module is not a custom bundle and comes with the superseded part number 5669858. The Cummins Wls Acs Module 5669858 is primarily on EPA21 6.7 liter ISB/QSB engines.