What is the Duramax CP4 pump recall?
The recall targets certain Duramax diesel GM trucks equipped with Bosch CP4 high‑pressure fuel pumps and requires dealers to replace the CP4 pump and inspect related fuel-system components to reduce the risk of leaks or fires.
Overview: why this recall matters
The CP4 high‑pressure fuel pump is a critical component that feeds diesel at very high pressure to the injectors in Duramax engines. In some vehicles, failures or contamination can cause the pump to degrade, seize, or leak, creating a fire hazard or leaving the engine unable to run. To protect drivers, manufacturers issue recalls that move customers from affected CP4 pumps to updated hardware and inspect adjacent lines and seals for damage.
Which vehicles are affected
The recall typically covers heavy‑duty GM pickups and SUVs with the Duramax diesel engine. The exact VINs and model years vary by campaign, so owners should verify applicability for their specific vehicle.
- Chevrolet Silverado 2500HD and 3500HD with Duramax diesel
- GMC Sierra 2500HD and 3500HD with Duramax diesel
Because the scope of a recall can change as new information emerges, the precise years and VINs are best confirmed through official sources such as the National Highway Traffic Safety Administration (NHTSA) and General Motors’ recall site.
What owners should do
To determine if a vehicle is affected and to schedule service, follow these steps. The following list provides steps to verify recall status and arrange repair. You will need your vehicle identification number (VIN) to check eligibility.
- Check recall status by VIN on NHTSA’s SaferCar.gov database or GM’s official recall site.
- Contact a GM dealer or certified diesel technician to schedule a free recall repair if your VIN is listed.
- If you notice fuel odors, visible leaks, a loss of engine power, misfires, or the engine stalls, stop driving the vehicle and contact your dealer or roadside assistance for guidance.
Concluding: Recall repairs are performed at no charge to the owner, and the work commonly includes replacing the CP4 high‑pressure fuel pump and inspecting or updating related fuel system components as needed.
Remedy details
The standard remedy involves replacing the CP4 high‑pressure fuel pump with updated hardware and may include related components such as fuel rails, seals, lines, and possibly software calibrations. The goal is to restore reliable fuel delivery and reduce the risk of leaks or fire. Availability of parts and the exact scope of work are determined by the dealership based on the specific VIN and campaign.
Why it matters for drivers
Duramax CP4 failures have been linked to sudden engine stalling, reduced power, or fuel leaks that can pose safety risks. The recall aims to prevent these outcomes by ensuring the correct pump hardware is installed and that the surrounding fuel‑system components are intact and compatible with the updated pump.
Where to find official guidance
For the most accurate, up‑to‑date information, search by your VIN on SaferCar.gov (NHTSA) and GM’s official recall site. These sources provide the current list of affected vehicles, campaign numbers, and instructions for scheduling repairs at authorized dealers.
Summary
The Duramax CP4 pump recall is a safety initiative to replace certain Bosch CP4 high‑pressure fuel pumps in diesel GM trucks and inspect related components. If your vehicle is affected, you can verify via VIN lookup and receive a free repair at a GM dealer, reducing the risk of fuel leaks, engine failure, and fire.
What is the final approval for the CP4 settlement?
On May 6, 2025, Judge Terrence G. Berg granted final approval to a $50 million settlement with General Motors on behalf of consumers who paid out of pocket for repairs to defective CP4 fuel pumps, and on behalf of consumers who no longer own their truck(s) and did not pay for a fuel pump repair.
How to apply for reimbursement of GM CP4?
All claims require supporting documentation, including proof of purchase and proof of repair. If you no longer own the truck and did not pay out of pocket for a CP4 repair before the date of Final Approval, you do not need to submit Proof of Repair, but you are required to submit Proof of Sale.
What year does Duramax have CP4 issues?
Duramax engines with CP4 pump problems are from model years 2011 through 2016, specifically the LML and LGH engines. These engines are prone to catastrophic failure due to the CP4 pump's issues with the lubricity of diesel fuel, which can contaminate the entire fuel system.
This video explains the CP4 pump issues in 2011-2016 Duramax engines and a recent settlement for owners: 58sTruck MasterYouTube · Oct 10, 2024
- Affected Models: 2011–2016 Chevrolet Silverado 2500HD, 3500HD, and GMC Sierra 2500HD, 3500HD equipped with the LML or LGH Duramax engine. The LGH engine was also used in Express vans during a similar timeframe.
- The Problem: The CP4 pump is highly sensitive to the low lubricity of modern ultra-low sulfur diesel (ULSD) fuel. The lack of lubrication causes the pump's internal parts to wear down, creating metal particles that then contaminate the entire fuel system, often leading to a complete and costly failure.
- Solution: To prevent catastrophic failure, owners often upgrade to a CP3 pump conversion kit, which is considered more reliable.
- Note: Starting with the 2017 model year, GM switched to a different high-pressure fuel pump (Denso HP4) for the L5P engine, moving away from the CP4.
This video explains why the CP4 pump failed and the potential consequences: 59sTruck MasterYouTube · Sep 4, 2021
How much is GM payout for CP4?
General Motors CB4 fuel pump lawsuit settles for $50 million
Owners of older General Motors HD trucks may qualify for payouts between $400 and $12,000. The class-action lawsuit claims heavy-duty Chevrolet Silverado and GMC Sierra trucks with the 6.6-liter Duramax diesel engine had defective CP4 fuel pumps.
