Alliant Power remanufactured CP4.2 high-pressure fuel injection pump for 2011–2016 Chevy/GMC 6.6L Duramax LML and LGH. Built to OEM specs with 10+ quality checks per unit. Direct drop-in replacement — no modifications or tuning required. 24-month unlimited mileage warranty. Catching CP4 failure early saves thousands — a full fuel system replacement after catastrophic failure runs $8,000–$12,000+. Replaces GM 12638262, Bosch 0986437421. Learn more: CP4 Failure Guide | CP4 vs CP3 Conversion | Lift Pump Guide