The CP4 fuel pump lawsuit affecting Chevrolet Silverado and GMC Sierra trucks is a significant legal action addressing a widespread defect in the high-pressure diesel fuel injection system used in these vehicles. This lawsuit mainly concerns the failure of the Bosch CP4 high-pressure fuel pump installed in Duramax diesel engines of 2011 to 2016 model-year Silverado and Sierra trucks. The defect, linked to incompatibility with North American diesel fuel, caused premature pump failures that damaged fuel injectors and contaminated the entire fuel system, leading to costly repairs often exceeding $10,000. As of 2025, a $50 million class-action settlement has been approved, offering compensation to affected vehicle owners in certain U.S. states, while individual claims and ongoing litigation continue.
Background and Nature of the CP4 Fuel Pump Defect
General Motors (GM) equipped the 2011-2016 Chevrolet Silverado HD and GMC Sierra HD trucks with 6.6L Duramax diesel engines containing Bosch CP4 high-pressure fuel pumps sourced from Europe. These pumps were designed for European diesel fuels that provide more lubrication compared to American diesel variants, making them ill-suited for the fuel quality in the U.S. This mismatch led to premature wear and internal pump failures, producing metal shavings that contaminated the fuel system’s injectors, rails, pipes, and even fuel tanks. Once damaged, the entire fuel system often required replacement.
Owners of affected trucks faced unexpected breakdowns and repairs costing between $10,000 and $15,000 or more, with some dealers refusing to honor warranties since fuel contamination from the pump failure is considered an excluded damage. The CP4 pump defect has been a highly discussed issue in diesel truck communities, forums, and social media for years, prompting numerous complaints and legal claims.
Details of the $50 Million Settlement
In 2025, a U.S. federal court granted final approval to a $50 million class-action settlement with General Motors concerning the CP4 fuel pump defect. The settlement covers owners and lessees of qualifying 2011-2016 Chevrolet Silverado and GMC Sierra trucks equipped with the Duramax diesel engine and purchased or leased from authorized GM dealers in the states of California, Florida, Illinois, Iowa, New York, Pennsylvania, and Texas.
Eligible class members who paid out-of-pocket for repairs related to the CP4 fuel pump failure, or who no longer own their affected vehicle and suffered losses, can file claim forms by November 6, 2025, to receive cash payments. Additionally, GM has agreed to extend a limited warranty on the CP4 fuel pump through May 7, 2026, or 200,000 miles, whichever comes first, though coverage may only pay for half the repair costs.
Ongoing Litigation and Individual Claims
Outside the class settlement, law firms such as Stern Law are assisting owners of affected vehicles in states not covered by the settlement to pursue individual compensation claims. These individual lawsuits seek to hold GM accountable for design defects, warranty failures, and financial burdens placed on truck buyers due to the pump defect.
The litigation also raises wider questions about manufacturer responsibility in adapting engine components for variations in regional fuel standards, and the adequacy of GM’s responses to reported failures and customer complaints over several years.
Broader Implications for Truck Owners and the Auto Industry
The CP4 fuel pump defect and resultant lawsuits highlight critical issues in automotive manufacturing, particularly for diesel engine components reliant on specific fuel chemistries. For truck owners, the costly repairs and extended downtime underscore the risks associated with high-tech fuel injection systems and warranty limitations.
For the auto industry, the case signals increased legal and financial exposure for manufacturers who fail to fully test parts against regional fuel variations or who inadequately address widespread defects. The legal outcomes may influence future product development, warranty policies, and transparency regarding component reliability.
Frequently Asked Questions About the CP4 Fuel Pump Silverado Sierra Lawsuit
Which vehicles are affected by the CP4 fuel pump defect?
The defect affects 2011-2016 Chevrolet Silverado HD and GMC Sierra HD trucks equipped with the 6.6L Duramax LML diesel engines using Bosch CP4 high-pressure fuel pumps.
What is wrong with the CP4 fuel pump?
The CP4 pump is prone to premature failure due to its design being incompatible with North American diesel fuel, causing internal damage and releasing metal debris that contaminates the fuel system and damages injectors.
What compensation does the $50 million settlement provide?
The settlement offers cash payments to eligible owners who paid for repairs or no longer own their vehicle, plus an extended limited warranty covering CP4 fuel pump repairs with partial cost coverage.
Can owners outside the settlement states file claims?
Yes, owners from other states may pursue individual legal claims through law firms representing them in separate lawsuits against GM for the CP4 pump defect.
Does GM admit fault for the pump defect?
GM has not publicly admitted a design flaw but agreed to the settlement to resolve litigation and avoid prolonged disputes.
Conclusion
The CP4 fuel pump Silverado and Sierra lawsuit underscores the challenges and consequences of automotive component failures on owners and manufacturers alike. With costly repairs, extended warranties, and substantial settlements, it serves as a high-profile example of manufacturer accountability for design defects affecting widely sold vehicles. For Chevrolet and GMC Duramax diesel truck owners, the ongoing legal actions offer pathways to recover losses and push for further protections. The case also encourages industry-wide attention to fuel compatibility and component durability as critical factors in vehicle reliability and customer satisfaction.
