2011-2016 LML CP4 to CP3 Conversion KitLML Duramax CP4 CP3 Conversion Kit (20112016) If you own a 20112016 LML Duramax, you already know the factory CP4 injection pump has a reputation for failure and when it goes, it can contaminate the entire fuel system with metal debris. That means injectors, rails, sensors, and lines can all be affected, turning a single failure into a major repair. This conversion kit allows you to replace the failure prone CP4 with the proven and reliable CP3 pump