GM CP4 Fuel Pump Lawsuit Status in 2026 and What Duramax Owners Can Still Do

TL;DR

• The GM CP4 fuel pump lawsuit, filed as Chapman v. General Motors LLC, is over. Judge Terrence G. Berg granted final approval on May 6, 2025, and every claim window has now closed (GM Fuel Pump Settlement, 2026).
• GM funded $35 million for class members, split into a $30 million Repair Fund and a $5 million Former Owner Fund. Attorney fees of up to $15 million sat outside that pot, which is why some articles call it a $50 million settlement (GM Fuel Pump Settlement, 2026).
• Owners who paid out of pocket for a CP4 repair were estimated to receive between $6,356 and $12,712. Former owners who never paid for a repair were estimated at $400 to $800 (GM Fuel Pump Settlement, 2026).
• Only 2011 to 2016 Chevrolet Silverado and GMC Sierra trucks with the 6.6L Duramax bought from a dealer in California, Florida, Illinois, Iowa, New York, Pennsylvania, or Texas were in the class. Everyone else was never released and never paid.
• GM never issued a safety recall for this pump. Ram replaced 222,410 pumps under NHTSA recall 21V880, and Ford reflashed software on 295,449 trucks under NHTSA recall 24V-957. Three automakers, one pump, three different answers.

Is There an Active GM CP4 Fuel Pump Lawsuit Right Now

No. The GM CP4 fuel pump lawsuit was resolved. The case, Chapman, et al. v. General Motors LLC, Case No. 2:19-cv-12333-TGB-DRG, was heard in the U.S. District Court for the Eastern District of Michigan and received final approval on May 6, 2025 (GM Fuel Pump Settlement, 2026). Initial settlement checks went in the mail on March 23, 2026. Every deadline that mattered to a truck owner has passed.

That single fact is why most of what you find on this topic is now wrong. A lot of pages still tell Duramax owners to file a claim. There is nothing left to file. Here is the actual timeline, start to finish.

Source for all dates: the official settlement administrator site at GMFuelPumpLitigation.com, run by JND Legal Administration (GM Fuel Pump Settlement, 2026).

If you filed a valid claim and got a notice saying your paperwork was short, that is the one live thread left. The administrator is still reviewing responses to Notices of Deficient Claim, and an additional distribution is going out in August 2026 to people who cured them.

What the GM CP4 Fuel Pump Settlement Actually Paid

GM put $35 million on the table for class members, and up to $15 million more for the lawyers. Press coverage rounded that to a $50 million settlement, which is where the confusion comes from. Both numbers are real; they just count different things (GM Fuel Pump Settlement, 2026).

The $35 million was split into two funds with very different payouts.

Two details in that table decided who actually got paid. First, the payment amount floated with claim volume, so the headline number of $12,712 only landed if roughly a quarter of eligible owners filed. Second, the Reimbursement Program covered 50 percent of the bill and only for parts listed in GM Technical Service Bulletin 16-NA-102, performed at a GM-authorized dealership (GM Fuel Pump Settlement, 2026). Take your truck to the independent diesel shop down the road, and the reimbursement did not apply, no matter how much better their price was.

The settlement also carved out what it did not release. Claims for death, personal injury, damage to property other than the truck itself, and subrogation all stayed alive (GM Fuel Pump Settlement, 2026). If a CP4 failure caused something worse than a repair bill, that claim was never inside this case.

Which Trucks Had the CP4 and Which Ones Did Not

GM installed the Bosch CP4.2 high-pressure fuel pump in the 6.6L Duramax LML and LGH engines from 2011 through 2016. Starting with the 2017 L5P Duramax, GM dropped Bosch entirely and moved to a Denso HP4 pump (XDP, 2024). If your Duramax is a 2017 or newer, you do not have a CP4, and this lawsuit was never about your truck.

The class definition was narrower still. To be a class member, you needed a 2011 to 2016 Chevrolet Silverado or GMC Sierra with the 6.6L Duramax, purchased from a GM-authorized dealer in one of seven states, between March 1, 2010 and September 13, 2024 (GM Fuel Pump Settlement, 2026).

The seven states were California, Florida, Illinois, Iowa, New York, Pennsylvania, and Texas. The test was where you bought the truck, not where you live now. Plenty of owners in Arizona, Ohio, and Georgia ran a VIN through the lookup tool, saw a match on the truck, and then found out the purchase state knocked them out.

What Vehicles Are Equipped With the Problematic High-Pressure Fuel Pump

The CP4 was never a GM-only part. Bosch sold it across the industry, which is why the same failure story keeps appearing under different badges.

Application list compiled from diesel parts specialist documentation (XDP, 2024). Verify your own truck by the engine RPO code and build date rather than the model year alone, because mid-year production changes exist.

Why the Bosch CP4 Pump Destroys Itself

The CP4 fails because diesel fuel is its only lubricant, and American diesel is thinner than the fuel the pump was designed around. Plaintiffs alleged the pump’s internal parts rub against each other and shed metal shavings that contaminate the entire high-pressure fuel injection system, sometimes shutting the engine down mid-drive (GM Fuel Pump Settlement, 2026). GM denied the allegations and denied that the pumps are defective. The court never ruled on who was right.

Think of a blender running with nothing in it. The motor is fine for a while. The blades are fine for a while. Then the bearing that was supposed to be swimming in something starts eating itself, and the shavings go wherever the machine sends them. In a CP4, the machine sends them at up to 30,000 psi into your injectors, your rails, and your fuel tank.

That is why a CP4 failure is not a pump replacement. It is a fuel system replacement. The class notice in the GM case put repair costs at $9,000 to $10,000 (GM Fuel Pump Settlement, 2026). Diesel shops quote $7,500 to $12,000 and up depending on how far the debris traveled (Diesel Power Products, 2025). Owners who posted repair orders in the case reported bills north of $15,000.

There is a bleak joke among LML owners that the pump has two states: working and expensive. The joke lands because there is no warning stage in between. You do not get a check engine light three weeks out. You get a truck that dies at 70 mph towing a trailer, and a tow bill on top of the repair bill.

How to Identify Symptoms of a Failing Diesel Fuel Injection Pump

The honest answer is that most CP4 failures give you very little notice, and the symptoms that do appear tend to arrive hours or days before the end, not months. Ford’s own recall filing lists the warning signs it expects owners to notice, and they line up with what Duramax owners report.

• Extended cranking when starting, where the engine turns over noticeably longer than usual before catching (NHTSA, 2024).
• A check engine light, often with a fuel pressure code such as P0087 in the low fuel rail pressure family.
• Unusual noise from the fuel pump area, described by owners as a rattle or a hard tick that was not there last month.
• Reduced engine power, especially under load, which drivers usually notice first when towing or climbing a grade.
• A sudden stall with no restart, which is the failure itself rather than a warning of it.

There is one check you can run yourself for about the price of a filter. Pull the fuel filter and look at the media in good light. Metal contamination shows up as fine glitter, and it is unmistakable once you see it. Diesel technicians treat glitter in the filter as confirmation rather than suspicion. If it is there, stop driving the truck. Every mile after that pushes debris further into parts that cost more than the pump.

One warning that is genuinely useful. If a shop tells you they can replace only the pump and send you on your way, get a second opinion in writing. GM’s own bulletin for this condition, TSB 16-NA-102, lists a set of related components rather than a single part, which is a strong signal about how far contamination travels (GM Fuel Pump Settlement, 2026).

How Can I Check if My Vehicle Is Affected by the CP4 Fuel Pump Lawsuit

Run your VIN through the settlement administrator’s lookup tool at GMFuelPumpLitigation.com. It will tell you whether the truck itself was a Class Truck. What it cannot tell you is whether you personally qualified, because that turned on your purchase paperwork and the state you bought in.

1. Confirm the engine. You need the 6.6L Duramax in a 2011 to 2016 Silverado or Sierra. A 2017 or newer L5P is a different pump entirely.
2. Confirm the purchase state. The truck had to be bought from a GM-authorized dealer in California, Florida, Illinois, Iowa, New York, Pennsylvania, or Texas.
3. Confirm the purchase date. It had to fall between March 1, 2010 and September 13, 2024.
4. Pull your repair records. Even now, the repair order showing a CP4 replacement and what you paid is the single most valuable document you own on this issue.
5. Check whether you already got paid. Initial distribution checks went out March 23, 2026, and some class members were paid directly without filing anything (GM Fuel Pump Settlement, 2026).

If steps one through three all came back yes and you filed nothing by November 6, 2025, the difficult truth is that you are still bound by the settlement. Class members who did not opt out by December 12, 2024 released their claims against GM whether or not they ever saw a dollar (GM Fuel Pump Settlement, 2026). That is how class actions work, and it is the strongest argument going for reading legal notices that arrive in the mail looking like junk.

GM, Ford, and Ram Handled the Same Pump Three Different Ways

Three automakers put the same Bosch pump in their trucks and gave owners three completely different outcomes. This comparison is the part almost no one puts in one place, and it matters because owners searching for a GM CP4 fuel pump recall are often looking at the wrong brand’s news.

Every number in that table comes from a filed record. Ram’s campaign is documented at 222,410 vehicles under NHTSA campaign 21V880, with the remedy being a physical swap to the older CP3 design (NHTSA, 2021). Ford’s Part 573 report puts the population at 295,449 vehicles built between February 19, 2019 and August 23, 2021, with an estimated 4 percent defect rate, and the remedy listed as a PCM software update that increases cooling in the tappet area (NHTSA, 2024).

Read that Ford line again. The recall remedy does not replace the pump. It changes software so deposits are less likely to form. Ford owners have had opinions about this, and if you drive a Super Duty, our breakdown of Ford 6.7 diesel problems and whether the 6.7 Power Stroke is reliable covers where that leaves you.

For GM owners, the takeaway is blunt. Searching for a GM CP4 fuel pump recall returns nothing because there is no recall campaign. GM’s obligation on this pump came from a federal judge in Detroit, not from a regulator, and it reached only seven states.

What You Can Still Do in 2026 if the Settlement Missed You

Your options in August 2026 depend entirely on which bucket you fall into. Four groups still have something to talk about, and one group unfortunately does not.

• You bought outside the seven states. You were never a class member, which means you never released anything. Whether a claim is still viable turns on your state’s statute of limitations and your purchase and repair dates, and on a 2011 to 2016 truck those clocks are usually the problem rather than the merits.
• You opted out by December 12, 2024. You kept your individual rights. That was the whole point of opting out, and it is worth having someone read the file.
• Someone was hurt, or something other than the truck was damaged. The settlement expressly did not release claims for death, personal injury, property damage beyond the truck, or subrogation (GM Fuel Pump Settlement, 2026). Those claims live on their own track.
• You drive a newer diesel with a fuel system failure. This is the group with the most leverage and the least awareness. A 2020 to 2022 Ford Super Duty or a current-model truck that is still inside its warranty period is a lemon law and warranty question, not a class action question.
• You were in the class, filed nothing, and the deadline passed. There is no route back in. The release binds you (GM Fuel Pump Settlement, 2026).

Two federal and state routes are worth knowing about regardless of which bucket you are in. The Magnuson-Moss Warranty Act covers written warranties nationwide and shifts attorney fees to the manufacturer when a consumer wins. State lemon laws do the same thing on a shorter timeline with stronger remedies. Our guide to how lemon law works walks through the difference.

Where Arizona Lemon Law Fits and Where It Does Not

Arizona lemon law will not help with a 2011 to 2016 Duramax, and any firm telling you otherwise is selling something. Arizona’s Motor Vehicle Warranties Act covers the shorter of your express warranty term or two years and 24,000 miles from delivery, and the filing window closes six months after that (A.R.S. § 44-1262, § 44-1265). A truck built in 2016 ran out of runway years ago.

Where Arizona law does bite is on the truck you are driving now. If you bought a current diesel and the fuel system has been apart more than once, the statute is on a much shorter fuse than most owners realize.

• Four repairs for the same defect, or 30 cumulative calendar days out of service, creates a presumption that the manufacturer had a reasonable number of attempts (A.R.S. § 44-1264(A)). You need one or the other, not both.
• A qualifying buyback returns the purchase price plus collateral charges including sales tax, title, registration, and finance charges, minus an allowance for your use (A.R.S. § 44-1263).
• The use allowance stops growing on the date of your first written report of the defect. A phone call to the service desk does not count. A dated email does.
• A prevailing consumer’s costs and attorney fees are awarded against the manufacturer (A.R.S. § 44-1265), which is why these cases are handled without upfront fees.
• The filing deadline is six months from the earlier of warranty expiry or the two-year, 24,000-mile mark. It is one of the shortest windows in the country.

Arizona also has no personal use restriction, so a truck titled to your business can still qualify. That matters in the diesel world, where a large share of HD pickups are work trucks. Full detail sits on our Arizona lemon law page, and the same analysis for other states is on the Texas, California, Florida, and Illinois pages.

What Your Repair File Needs to Be Worth Anything

Every warranty and lemon law outcome runs on documents, and the documents are usually worse than the owner remembers. Before you talk to anyone, gather these five things.

1. Every repair order, including the ones where the dealer wrote no fault found. Those are often the most useful pages in the file because they establish the date you first complained.
2. The mileage at each visit, which is normally printed on the repair order and is what the use allowance calculation runs on.
3. Your dated written complaints. Emails to the dealer or manufacturer, portal messages, anything with a timestamp. This is the single most common gap.
4. The warranty booklet or the terms showing your coverage period, because the deadline math starts from warranty expiry.
5. Purchase paperwork showing the selling dealer, the state, and the date, which is what decides class membership in the GM case and decides which state’s law applies to you.

One caution specific to diesel owners. Aftermarket modification is the defense manufacturers reach for first, and Arizona’s statute lets them raise abuse, neglect, and unauthorized modification as a defense (A.R.S. § 44-1263(B)). A CP3 conversion, a delete, or a tune complicates a warranty claim considerably. Our guide to what voids a car warranty covers where the actual line sits, because it is not as broad as dealers imply.

Mistakes That Cost Duramax Owners Money on This Issue

• Throwing away the class notice. The mailer that looked like junk in late 2024 was the opt-out decision, and it silently released claims for everyone who ignored it.
• Waiting for a recall that was never coming. GM never opened a safety recall on the LML CP4, so owners who held out for a free fix waited through the entire claim window.
• Repairing at an independent shop while expecting settlement reimbursement. The Reimbursement Program required a GM-authorized dealership, which caught owners who chose the cheaper shop.
• Complaining only by phone. In Arizona, the use allowance deduction stops at the first written report, so verbal complaints cost real money on the final number.
• Assuming a newer truck has no path. The strongest claims right now belong to owners of current diesels with repeat fuel system repairs, and most of them have never heard of a lemon law claim.

Frequently Asked Questions About the GM CP4 Fuel Pump Lawsuit

What is the GM CP4 fuel pump lawsuit about?

Plaintiffs alleged that the Bosch CP4 high-pressure fuel injection pump in 2011 to 2016 Duramax trucks is unreasonably fragile, generates metal shavings that contaminate the entire fuel system, and can shut the engine down. They also alleged GM knowingly concealed the defect. GM denied everything, and the court never decided the merits (GM Fuel Pump Settlement, 2026).

Is There an Active Lawsuit Related to the Fuel Pump Used in Certain GM Vehicles?

Not anymore. Chapman v. General Motors LLC received final approval on May 6, 2025, and all claim deadlines have closed. The last settlement activity is an August 2026 distribution to class members who cured deficient claims (GM Fuel Pump Settlement, 2026).

What Compensation Is Available for Owners Involved in the CP4 Fuel Pump Class Action?

Compensation is closed to new claimants. Owners who filed valid claims for a paid CP4 repair were estimated to receive $6,356 to $12,712, and former owners who never paid for a repair were estimated at $400 to $800 (GM Fuel Pump Settlement, 2026).

Which Companies Are Being Sued Over Defective CP4 Fuel Pumps?

GM’s case is settled and closed. Litigation against Ford over the CP4 in 6.7L Power Stroke engines has continued separately from the GM case, and Ram addressed its CP4 trucks through NHTSA recall 21V880 rather than through a consumer settlement (NHTSA, 2021).

What Are My Rights if My Diesel Vehicle Experienced a Fuel System Failure?

That depends on the age of the vehicle. Inside the warranty period, state lemon law and the Magnuson-Moss Warranty Act both apply, and both shift attorney fees to the manufacturer when you win. Outside it, your route is an open recall, a manufacturer goodwill request, or a class settlement if one exists for your vehicle.

How Do I Find Legal Representation for a Vehicle Defect Class Action?

For an active class action, you do not need to hire anyone, because appointed class counsel already represents the class. You hire your own attorney when you want an individual claim, which is the situation if you opted out, bought outside the class states, or have a newer vehicle still under warranty.

Is there a GM CP4 fuel pump recall?

No. There is no NHTSA safety recall campaign covering the CP4 pump in 2011 to 2016 Duramax trucks. Owners searching for a GM CP4 fuel pump recall are usually finding coverage of Ford recall 24V-957 or Ram recall 21V880, which are different manufacturers and different model years.

How much was the GM CP4 fuel pump settlement worth?

$35 million was allocated to class members, made up of a $30 million Repair Fund and a $5 million Former Owner Fund. Attorney fees and expenses of up to $15 million were awarded separately, which is why some reports describe it as a $50 million settlement (GM Fuel Pump Settlement, 2026).

Can I still file a claim in the GM CP4 settlement?

No. The deadline for past-repair and former-owner claims was November 6, 2025, and the deadline for future-repair reimbursement forms was July 5, 2026. Both have passed, and late claims are treated the same as filing nothing (GM Fuel Pump Settlement, 2026).

Which Duramax model years have the CP4 pump?

The 6.6L Duramax LML and LGH engines used the Bosch CP4.2 from 2011 through 2016. The 2017 and newer L5P Duramax uses a Denso HP4 pump instead (XDP, 2024).

How much does it cost to fix a failed CP4 fuel pump?

The class notice in the GM case cited repair costs of $9,000 to $10,000 (GM Fuel Pump Settlement, 2026). Diesel specialists put the range at $7,500 to $12,000 and higher when contamination reaches the injectors and tank (Diesel Power Products, 2025), because a failed CP4 usually means replacing the fuel system rather than the pump.

Does Arizona lemon law cover a 2011 to 2016 Duramax with CP4 failure?

Almost certainly not. Arizona’s coverage window is the shorter of the express warranty term or two years and 24,000 miles, and the action has to begin within six months after that (A.R.S. § 44-1262, § 44-1265). Arizona lemon law is the right tool for a current diesel truck with repeat repairs, not a ten-year-old one.

What should I do if my current diesel truck keeps going back for fuel system repairs?

Put your complaint in writing today, then collect every repair order with the mileage on it. In Arizona, the use allowance deduction stops on the date of your first written report, and four repairs for the same fault or 30 cumulative days out of service triggers the statutory presumption (A.R.S. § 44-1264(A)). Send the file to a lemon law attorney before you book the next appointment, not after.

Key Takeaways

• The GM CP4 fuel pump lawsuit is closed, fully approved, and paying out its final distribution in August 2026.
• The class covered only 2011 to 2016 Silverado and Sierra 6.6L Duramax trucks bought in seven states, so most affected owners nationwide were never included and never released.
• GM issued no recall for this pump, while Ram replaced 222,410 pumps and Ford reflashed software on 295,449 trucks.
• Personal injury, death, non-truck property damage, and subrogation claims were never released by the settlement.
• The live opportunity in 2026 is not the old lawsuit. It is a newer diesel still under warranty with a repair history the manufacturer would rather you never organize.

Consumer Protection Law Group works vehicle defect and warranty claims full time. Send your repair orders, and we will read them at no cost and tell you where your deadline actually sits. Start a free case review or call (424) 677-1115.

This article is for general information and is not legal advice. Reading it does not create an attorney-client relationship. Settlement deadlines, recall status, and case posture change. Verify current status at GMFuelPumpLitigation.com and NHTSA.gov before acting. Past results do not guarantee a similar outcome.