GM CP4 Fuel Pump Lawsuit: Critical Facts Every Affected Owner Must Know

GM lost a major class-action lawsuit over defective CP4 fuel pumps, forcing extended warranties and partial reimbursements, yet owners of 2011-2016 diesel trucks and SUVs still face catastrophic failure risks demanding immediate action. This legal outcome addresses widespread pump failures contaminating entire fuel systems with metal shards. Owners bear significant costs despite settlements, making understanding lawsuits, symptoms, and prevention essential.

What is the GM CP4 Fuel Pump and Why Did It Fail?

The CP4.2 high-pressure fuel pump, supplied by Bosch, was installed in GM’s Duramax diesel engines from approximately 2011 to 2016. This critical component pressurizes diesel fuel for efficient combustion. Unlike the older CP3 pump used pre-2011, the CP4 design proved fundamentally incompatible with U.S. diesel fuel’s lubricity properties. U.S. diesel has lower lubricity than European diesel specifications the pump was designed for. This insufficient lubrication causes excessive metal-on-metal wear within the pump mechanism. Internal components grind down, generating fine metallic particles. These fragments then contaminate the entire fuel delivery system, including injectors, rails, and lines. Contamination quickly damages other expensive components beyond the pump itself.

Common Symptoms of CP4 Fuel Pump Failure

Recognizing early warning signs is vital to prevent extensive damage. Symptoms progress as internal wear increases and contamination spreads:

• Engine Power Loss: Gradual or sudden reduction in power during acceleration or while towing due to disrupted fuel pressure.
• Hard Starting: Extended cranking times before the engine starts, indicating inadequate fuel pressure.
• Misfires or Rough Idling: Unstable engine operation at idle or while driving from uneven fuel delivery.
• Check Engine Light: Illumination, often accompanied by diagnostic trouble codes like P0087 (low fuel pressure).
• Metallic Sounds: Audible grinding, whining, or knocking noises from the engine bay signaling advanced internal wear.
• Complete Engine Stalling: Total failure to start or sudden shutdown while driving, typically requiring immediate repair.

The GM CP4 Fuel Pump Lawsuit Timeline and Outcome

Owners filed class-action lawsuits starting in 2016 (Sullivan, et al. v. General Motors LLC). Lawsuits alleged GM knowingly installed defectively designed pumps prone to sudden failure despite Bosch warnings. Plaintiffs argued U.S. diesel specifications rendered the CP4 unfit. GM denied wrongdoing. In January 2022, Judge Fernando M. Olguin approved a final settlement covering approximately 600,000 vehicles, including Chevrolet Silverado HD and GMC Sierra HD trucks, plus Chevrolet Suburban, Tahoe, and Express/GMC Savana vans equipped with 6.6L Duramax engines.
Key settlement terms include:

• Extended Warranty: CP4 pump components covered for 10 years/200,000 miles from original in-service date (whichever comes first).
• Reimbursements: Partial payments for past out-of-pocket repairs (75% of parts/labor for pump replacement, 40% for full system replacement if contaminated). Proof required.
• Customer Satisfaction Program (N192268940): Covers certain 2016-2018 models with earlier versions of the settlement.

Warranty Coverage and Repair Costs Explained

The settlement extended warranty only covers the CP4 pump and pressure lines. It explicitly excludes damage to other fuel system parts caused by pump failure debris, such as fuel injectors, rails, or feed lines. Repairing a failed CP4 typically requires complete system replacement. Costs vary significantly:

• Pump Replacement Only: $3,000-$5,000 parts and labor.
• Full System Replacement (Pump + Injectors + Rails + Lines): $8,000-$12,000+ due to extensive contamination.
  The settlement reimburses only a portion of these costs for repairs before specific dates. Repairs after the settlement announcement are covered only under the extended warranty terms for pump failure. Owners remain fully responsible for contamination damage costs beyond the pump itself. Dealers may perform warranty-covered pump replacements, but many owners report inconsistent coverage interpretations.

Preventing Failure: Aftermarket CP3 Conversion Kits

The most effective long-term solution is replacing the CP4 with a CP3 conversion kit. CP3 pumps possess superior durability and compatibility with U.S. diesel fuel. Benefits include:

• Elimination of CP4 Failure Risk: CP3 design is proven reliable and not prone to the same catastrophic wear.
• Improved Lubricity Tolerance: Handles lower-lubricity diesel without premature degradation.
• Protection from Contamination: Prevents metal debris destroying the entire fuel system.
  Conversion kits (including pump, mounting hardware, and lines) cost $1,500-$2,500 for parts. Installation labor adds $800-$1,500. Total CP3 conversion typically ranges from $2,500to$4,000. This proactive repair avoids potential $12,000 system replacement costs later. Conversion voids the GM extended warranty on the fuel system. Weigh warranty status against failure risk when considering timing.

Critical Steps for Owners of Affected GM Diesel Vehicles

Immediate action is necessary regardless of warranty status:

1. Determine Your Vehicle’s Pump Type: Confirm if your 2011-2016 GM diesel vehicle has the CP4 pump (most do). VIN-specific checks via GM dealerships are reliable.
2. Monitor for Symptoms: Be alert for hard starting, power loss, noises, or check engine lights. Address symptoms immediately.
3. Verify Warranty Status: Contact a GM dealership with your VIN. Understand what the N192268940 settlement covers.
4. File for Reimbursement (If Applicable): If you paid for qualifying pump/system repairs before the deadline, submit claims immediately. Provide detailed repair invoices.
5. Evaluate the CP3 Conversion: Consult reputable diesel specialists. Given the CP4’s inherent weakness, conversion is often the most economical long-term solution.
6. Use High-Quality Fuel and Additives: Only purchase diesel from reputable stations. Use approved fuel additives specifically designed to enhance diesel lubricity (consult your manual) to potentially slow CP4 wear.
7. Consider Legal Consultation: If denied valid warranty or settlement claims, consult a consumer protection attorney familiar with auto defect litigation.

GM’s settlement provides limited financial relief but fails to eliminate the fundamental defect risk. Thousands remain vulnerable to sudden, costly failures. Proactive diagnosis, diligent claims filing, and serious consideration of the CP3 conversion offer the best protection against the financial and operational disaster caused by the flawed CP4 fuel pump. Owners must prioritize these steps to safeguard their vehicles and finances.