A delete kit removes emissions control systems from your 2020 Duramax diesel engine

A delete kit for a 2020 Duramax removes or bypasses the diesel particulate filter (DPF), exhaust gas recirculation (EGR) system, or selective catalytic reduction (SCR) system—or some combination of all three. These are emissions control components that the engine uses to meet federal and state air quality standards. Removing them increases engine power and fuel economy, but it also makes the vehicle illegal to drive on public roads in most U.S. states and voids your manufacturer warranty.

The 2020 Duramax (found in Chevrolet Silverado HD and GMC Sierra HD trucks) uses all three systems. A full delete removes all of them; a partial delete removes one or two. The work requires engine tuning software, physical removal or blocking of components, and sometimes welding or fabrication of exhaust piping.

This is not a modification you can undo easily or cheaply. Once deleted, the truck will not pass emissions testing in states that require it, and you cannot legally sell it to someone in a state with emissions rules without disclosing the modification.

Key Takeaways

  • A delete kit removes emissions control parts (DPF, EGR, SCR) that reduce engine power and fuel economy, but it is illegal on public roads in most states and voids your truck's warranty.
  • The 2020 Duramax delete involves engine tuning software, physical component removal, and sometimes exhaust system fabrication—a job that costs between $2,000 and $5,000 depending on which systems are deleted and who does the work.
  • States with emissions testing (California, New York, Massachusetts, and others) will fail your truck at inspection, and federal law prohibits the sale of delete kits for on-road use.
  • Deleted trucks cannot be registered or insured legally for street use in most places, and insurance companies may deny claims if they discover the modification.
  • Off-road use in private land is the only legal context where a delete is permitted in most jurisdictions, though some states ban it entirely.

Why people delete emissions systems and what they gain

Diesel engines with emissions controls lose power and efficiency because the DPF traps soot, the EGR recirculates hot exhaust back into the engine, and the SCR injects urea to break down nitrogen oxides. All three reduce combustion efficiency and engine output. Removing them restores the engine to a higher power state and improves fuel economy—typically 5 to 15 percent better mileage, depending on driving habits and which systems are deleted.

For owners who use their trucks exclusively off-road or on private property, the power gain is the main draw. A deleted 2020 Duramax produces noticeably stronger acceleration and towing capacity. The engine also runs cooler because it is not recirculating hot exhaust, which can extend component life in some cases.

The secondary benefit is reduced maintenance. DPF systems require periodic regeneration cycles that can be inconvenient, and they can fail and cost $1,500 to $3,000 to replace. Deleting the DPF eliminates that risk.

Federal and state laws that make deletes illegal for on-road use

The Clean Air Act gives the U.S. Environmental Protection Agency (EPA) authority to regulate vehicle emissions. Federal law prohibits the manufacture, sale, and installation of delete kits for vehicles intended for on-road use. The EPA has authority to fine manufacturers and installers, and it has pursued cases against shops and kit sellers.

States with their own emissions testing programs—California, New York, Massachusetts, Connecticut, Delaware, Maine, Maryland, New Jersey, New Mexico, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington—will fail a deleted truck at inspection. Some states, including California, also prohibit the sale of delete kits outright, even for off-road use.

Driving a deleted truck on public roads in a state with emissions testing is a violation that can result in a failed inspection, registration denial, and fines. In states without emissions testing, there is no inspection barrier, but the truck is still illegal under federal law, and law enforcement can cite you if they discover the modification during a traffic stop or roadside inspection.

What the installation process involves and what it costs

A full delete of the 2020 Duramax requires three main steps: software tuning, physical component removal, and exhaust system modification. A technician uploads custom tuning software to the engine control module (ECM) that disables the emissions systems and adjusts fuel injection and timing to compensate. This software is what makes the truck run without the DPF, EGR, and SCR.

Physical removal means taking out the DPF from the exhaust system (a job that involves removing the rear bumper and exhaust components), disconnecting the EGR cooler and lines, and removing or disabling the SCR system. Some shops block the EGR with a plate rather than removing it entirely, which is faster but less complete. The exhaust piping is then welded or fitted to bypass the deleted components.

Cost varies widely. A full delete at a diesel shop typically runs $2,500 to $5,000 in labor, plus the cost of the tuning software (usually $400 to $1,200) and any fabricated exhaust parts ($300 to $800). Some shops bundle the software cost into their labor quote. A partial delete (DPF only, for example) costs less—usually $1,500 to $2,500—because it requires fewer physical modifications.

Insurance and warranty consequences

Your manufacturer warranty is void the moment a delete is installed. Chevrolet and GMC will not cover any engine or emissions-related repairs once they discover the modification. Even repairs unrelated to the deleted systems may be denied if the shop finds evidence of the delete during diagnosis.

Insurance coverage is more complicated. Most insurance policies do not explicitly exclude deleted vehicles, but they do exclude coverage for illegal modifications. If you have an accident and the insurer discovers the delete during the claims investigation, they may deny the claim or cancel your policy. Some insurers will not insure a deleted truck at all once they know about it.

The safest approach is to tell your insurance company about the delete before you need to file a claim. Some will accept it if the truck is used only off-road; others will decline to insure it. Either way, you will have a clear answer rather than a surprise denial later.

Resale and disclosure issues

A deleted truck is harder to sell, and you are legally required to disclose the modification to any buyer. In states with emissions testing, a deleted truck cannot be registered by the new owner, which severely limits your buyer pool. Even in states without testing, many buyers will not purchase a deleted truck because of the legal risk and warranty loss.

If you sell a deleted truck without disclosing it, you expose yourself to liability. A buyer who discovers the delete after purchase may pursue a fraud claim, and you could be required to pay for the cost of a re-installation of emissions components (which can exceed $5,000) or a refund of the purchase price.

Some dealers and private sellers list deleted trucks as-is with full disclosure, and they do sell—usually at a discount. The market for deleted trucks is smaller and more specialized, so expect to spend more time finding a buyer.

Off-road use and private property exceptions

Off-road use on private land is the primary legal context for a delete. If you own land or have permission to use someone else's private property, you can operate a deleted truck there without violating federal law. Many owners use deleted trucks for farm work, construction sites, or private trails where emissions testing does not explore.

Some states have additional restrictions. California bans deletes even for off-road use in some contexts, and a few other states have similar rules. Check your state's off-road vehicle regulations before assuming your deleted truck is legal off-road.

The key distinction is that the EPA's enforcement focus is on on-road use. Off-road-only trucks are lower priority, but they are not entirely exempt from scrutiny, especially in states with strict emissions laws.

Frequently Asked Questions

Can I get a deleted truck to pass emissions testing?

No. Once deleted, the truck will fail emissions testing because the DPF, EGR, and SCR systems are not present or are disabled. Re-installing all three systems to factory specifications is the only way to pass, and that costs $4,000 to $7,000. Some shops offer "rolling coal" tuning that makes the truck pass the visual inspection but still fails the actual emissions test.

Will a delete void my warranty when ready or only if something breaks?

The warranty is void when ready upon installation, even if nothing breaks. Chevrolet and GMC consider the delete a breach of the warranty terms. Any repair claim you file after a delete can be denied, even if the repair is unrelated to the deleted systems.

Is it legal to delete a truck for off-road use only?

Off-road use on private property is the main legal exception, but it depends on your state. California prohibits deletes even off-road in many cases. Check your state's regulations and local ordinances before proceeding. Federal law still technically applies, but enforcement is focused on on-road use.

What happens if I get caught driving a deleted truck on the road?

In states with emissions testing, you will fail inspection and cannot register the truck. In states without testing, law enforcement can cite you under federal law if they discover the modification during a traffic stop. Fines vary but can exceed $10,000 for the owner and more for the shop that installed it.

Can I sell a deleted truck without telling the buyer?

You are legally required to disclose the modification. Selling without disclosure can result in a fraud claim, and you may be ordered to refund the purchase price or pay for re-installation of emissions systems. Disclosure reduces your buyer pool but protects you legally.