S&S Diesel Motorsport LML-CP3-CARB CP4 to CP3 Conversion Kit (With Pump) – 50-State Legal

Protect your 2011–2016 LML Duramax from the industry’s most notorious fuel system failure.

The Bosch CP4.2 high-pressure fuel pump has earned a reputation as the Achilles’ heel of the 2011–2016 GM 6.6L Duramax LML. When it fails, metal debris frequently contaminates the entire high-pressure system—destroying injectors, rails, and lines and leaving owners with repair bills that often exceed $8,000–$10,000.

S&S Diesel Motorsport, a leader in common-rail diesel injection technology, engineered the definitive solution: a complete, bolt-in conversion that removes the problematic CP4.2 and replaces it with a proven, bulletproof Bosch CP3 high-pressure fuel pump.

Key Features & Benefits

• 50-State CARB Compliant (EO #D-756 / D-756-4) — Legal in all 50 states while retaining full factory emissions equipment (DPF, SCR, etc.)
• No Tuning Required — Drop-in installation with factory-style rail pressure control; no ECM calibration or custom tuning needed
• Complete Kit — Includes brand-new CP3 pump, mounting adapter/bracket, high-pressure and low-pressure fuel lines, fittings, extension harnesses, and detailed installation instructions
• Proven Reliability — The time-tested CP3 design offers significantly better durability and tolerance to real-world fuel quality than the CP4.2
• Peace of Mind — Eliminate the risk of catastrophic fuel system contamination before it happens

Vehicle Fitment

• 2011–2016 Chevrolet Silverado 2500HD / 3500HD (6.6L Duramax LML)
• 2011–2016 GMC Sierra 2500HD / 3500HD (6.6L Duramax LML)

Stop gambling with a known weak point. Convert to the CP3 and drive with confidence knowing your fuel system is built for the long haul.