Fleece LML CP3 Conversion Kit with CP3 (2011-2016 GM HD)Convert your LML's fuel system from a CP4 to a CP3 Improve your LML Duramax's reliability and fueling capability with a CP3 conversion. Since its introduction, the CP4 has proven to be less reliable and less capable than the CP3 used in previous Duramax platforms. Failures of the CP4 are extremely costly and require replacement of the entire fuel system. Avoid a costly failure down the road and convert your CP4 to a CP3 with our complete, no tuning