Hi Chris and everyone else. A Cummins CPL is a number assigned to an engine that helps Cummins identify the engine for aparts needed and other service. All Cummins engines have an assigned CPL number even engines  some old engines made before the system was introduced had a CPL number assigned to them, You need that number to get the correct parts. The same idea as a &quot;Build Number&quot; for Perkins and arrangement numbers for Cat engines. There are so many variations in the enegines these engine companies build. You know where I am going with this.