The GM CP4 fuel pump lawsuit involves certain Chevrolet Silverado and GMC Sierra diesel trucks equipped with the 6.6L Duramax V8 LML engine and Bosch CP4 high-pressure fuel pumps.
The major U.S. class action has already reached a $35 million settlement, and the settlement received final court approval in 2025. Payments to eligible class members began in March 2026, with another distribution scheduled for August 2026 for certain claims that needed additional documentation.
What Is the GM CP4 Fuel Pump Lawsuit?
The lawsuit, Chapman v. General Motors LLC, alleged that certain 2011–2016 Chevrolet Silverado and GMC Sierra diesel trucks were equipped with a defective Bosch CP4 high-pressure fuel injection pump.
According to the plaintiffs, the CP4 pump could wear internally and produce metal shavings. Those particles could spread through the high-pressure fuel system and potentially cause major fuel-system damage and engine shutdown.
GM denied wrongdoing and maintained defenses against the allegations. The settlement resolved the litigation without a court deciding that GM was liable.
Which Silverado and Sierra Trucks Are Involved?
The main settlement covers certain:
- 2011–2016 Chevrolet Silverado 2500HD
- 2011–2016 Chevrolet Silverado 3500HD
- 2011–2016 GMC Sierra 2500HD
- 2011–2016 GMC Sierra 3500HD
The vehicles must generally be equipped with the 6.6L Duramax diesel LML engine and the Bosch CP4 fuel pump.
The settlement’s eligibility requirements also depend on where the truck was purchased.
Which States Are Covered?
The U.S. settlement covers qualifying trucks purchased from a GM-authorized dealer in these seven states:
- California
- Florida
- Illinois
- Iowa
- New York
- Pennsylvania
- Texas
The official settlement website says qualifying purchases generally had to occur between March 1, 2010, and September 13, 2024.
This means owning a 2011–2016 Silverado or Sierra in another state does not automatically make you eligible for this particular settlement.
What Was the Alleged CP4 Defect?
The plaintiffs alleged that the CP4 pump was unusually susceptible to wear and failure.
The alleged failure process was:
- Internal CP4 components wear against each other.
- The wear can create metal particles.
- Metal particles can enter the fuel system.
- The contamination can spread to fuel-system components.
- The truck can experience serious fuel-system damage.
- In severe cases, the engine can shut down and fail to restart.
The lawsuit alleged that this could result in expensive repairs.
Importantly, these were claims made in the lawsuit. GM denied wrongdoing, and the settlement did not constitute a finding that GM was liable.
How Much Money Was in the GM CP4 Settlement?
The settlement fund was approximately $35 million.
Depending on the circumstances, eligible claimants could receive different amounts. Public settlement notices estimated payments could range from several hundred dollars to more than $12,000 for certain qualifying repair claims.
The amount was not a guaranteed $12,700 payment for every truck owner.
The actual payment depended on factors such as:
- Whether the claimant qualified
- Whether the CP4 pump failed
- Repair expenses
- Available documentation
- Whether the claimant still owned the truck
- Other settlement requirements
Can You Still File a New Claim?
This is where the timing matters.
The original claims process had a deadline in 2025, so someone who never submitted a claim by the applicable deadline generally should not assume they can file a new claim in 2026.
However, the official settlement administrator reports that initial distribution payments were issued March 23, 2026 and that claims with documentation problems are still being reviewed. An additional distribution is scheduled for August 2026 for qualifying class members who supplied documentation to correct deficient claims.
So the current situation is primarily about processing existing settlement claims, rather than opening a brand-new claims period.
What If You Already Filed a Claim?
If you submitted a claim and received a notice that your claim was deficient, you may still have an opportunity to provide the missing documentation.
The official settlement website specifically says that class-member responses to Notices of Deficient Claim are being reviewed.
If you believe you filed a claim, the best place to check its status is the official settlement website.https://www.gmfuelpumplitigation.com/
What If Your CP4 Pump Failed?
A failed CP4 pump could cause substantial repair costs because contamination may affect more than the pump itself.
Potential repairs can involve components such as:
- High-pressure fuel pump
- Fuel injectors
- Fuel rails
- Fuel lines
- Other high-pressure fuel-system components
The exact repair depends on the nature and extent of the failure.
If you paid for repairs yourself, invoices and other records could be important for establishing a settlement claim.
Does the Lawsuit Cover Personal Injuries?
No.
The official settlement information states that the lawsuit concerns economic damages and does not involve claims for personal injuries.
The case primarily concerned alleged financial losses associated with the defective CP4 pump.
Is the GM CP4 Lawsuit Still Active?
The original litigation has been resolved through the settlement, which received final approval in 2025.
However, settlement administration is continuing in 2026.
The official settlement website says initial payments were issued in March 2026 and that an additional distribution is planned for August 2026 for certain class members whose deficient claims have been corrected.
Therefore, it is more accurate to say:
The lawsuit has settled, but settlement administration is still ongoing.
What Is the Chapman v. GM Case?
The formal case is:
Chapman, et al. v. General Motors LLC
Case No. 2:19-cv-12333-TGB-DRG
The case was handled in the U.S. District Court for the Eastern District of Michigan.
Several CP4-related lawsuits were brought against GM, and Chapman became the main consolidated litigation for the settlement.
Is Bosch Also Named in CP4 Lawsuits?
Yes. There have been separate CP4-related lawsuits involving Bosch, the manufacturer of the fuel pump.
The GM settlement discussed here is specifically the settlement in the Chapman v. General Motors litigation.
That should not be confused with every lawsuit involving Bosch CP4 pumps.
GM CP4 Fuel Pump Lawsuit Timeline
| Date | Event |
| 2019 | Chapman lawsuit filed against GM |
| 2023 | Class certification reported for qualifying state claims |
| 2024 | Proposed $35 million settlement announced |
| January 2025 | Final approval process completed |
| May 2025 | Settlement received final approval |
| March 23, 2026 | Initial settlement payments issued |
| August 2026 | Additional distribution planned for qualifying deficient claims |
Frequently Asked Questions
What is the GM CP4 fuel pump lawsuit?
It is a class action alleging that Bosch CP4 fuel pumps installed in certain 2011–2016 GM Duramax diesel trucks were defective and could fail catastrophically.
Which trucks are affected?
Certain 2011–2016 Chevrolet Silverado and GMC Sierra diesel trucks with the 6.6L Duramax LML engine.
How much is the GM CP4 settlement?
The settlement fund is approximately $35 million.
Can owners get $12,700?
Some qualifying repair claims were estimated to receive payments of up to about $12,700, but that was not a guaranteed payment for every owner.
Is the GM CP4 lawsuit settled?
Yes. The settlement received final approval in 2025.
Are payments being made in 2026?
Yes. The official settlement administrator says initial payments were issued on March 23, 2026, with another distribution planned for August for certain claims requiring additional documentation.
Can I still submit a new claim in 2026?
The original claim deadline has passed. The current 2026 activity primarily concerns existing claims and deficient-claim documentation.
Does the lawsuit cover every Silverado and Sierra?
No. The settlement has specific model, engine, purchase-state and purchase-date requirements.
Does it cover the 2017 Silverado or Sierra?
The Chapman settlement discussed here covers 2011–2016 vehicles, not every newer Duramax truck.
Is the CP4 lawsuit the same as the GM 6.2L V8 engine lawsuit?
No. They are completely different issues. The CP4 case concerns diesel fuel pumps, while the newer 6.2L V8 litigation concerns alleged internal engine problems.
Bottom Line
The GM CP4 fuel pump lawsuit has been settled for about $35 million. It covers certain 2011–2016 Silverado and Sierra Duramax diesel trucks, with eligibility largely limited to purchases involving seven specified states. Initial payments began in March 2026, and settlement administration continues.