What an AFM Delete Kit 6.2 Does

An AFM Delete Kit 6.2 is a hardware and software package designed to remove or disable the Active Fuel Management (AFM) system on certain diesel engines, primarily General Motors vehicles from model years 2001 onwards. AFM is a fuel-saving feature that shuts down half of an engine's cylinders under light load — the kit physically removes the solenoid hardware that controls this switching and reprograms the engine control module (ECM) so the engine runs on all cylinders at all times.

The kit includes the solenoid delete brackets, gaskets, fasteners, and a custom ECM tune file. Installation requires removing the valve covers to access the AFM solenoids, installing the delete brackets in their place, and then connecting a tuning device to reprogram the ECM through the vehicle's diagnostic port. The result is that your engine no longer cycles between 8-cylinder and 4-cylinder operation.

This is a permanent modification. Once the solenoid hardware is removed and the ECM is retuned, the AFM system cannot be restored without replacing the solenoids and reflashing the original factory tune.

Key Takeaways

  • An AFM Delete Kit 6.2 physically removes the fuel management solenoids and reprograms your engine control module to run on all cylinders continuously.
  • Installation requires removing valve covers, installing delete brackets, and using a tuning device to flash new software to your ECM through the OBD-II port.
  • The modification is permanent and will trigger a check engine light unless the tune file is specifically designed to prevent diagnostic trouble codes.
  • Removing emissions or fuel management equipment may void your vehicle's warranty and could create registration or inspection issues depending on your state or local regulations.

What You Need Before You Start

Verify that your vehicle is compatible with the AFM Delete Kit 6.2. The kit is designed for specific GM diesel engines — typically 6.6L Duramax engines in trucks from 2001 to present, though compatibility varies by model year and engine generation. Check the kit documentation or contact the manufacturer with your vehicle's year, make, model, and engine size to confirm.

You will need basic hand tools: socket set, wrenches, screwdrivers, and a gasket scraper. You will also need a tuning device — either a handheld tuner (such as a HP Tuners device) or a laptop with tuning software, depending on which kit version you purchase. Some kits include the tuning device; others require you to own or purchase one separately. A new set of valve cover gaskets is strongly recommended, since you will be removing the covers and the old gaskets often tear during removal.

Set aside 4 to 8 hours for the job. The valve cover removal and reinstallation takes the longest. You will need a clean, well-lit workspace and a way to safely support the vehicle if you need to access the engine from underneath.

Removing the AFM Solenoids and Installing Delete Brackets

Disconnect the negative battery terminal and let the engine cool completely. Remove the valve covers by unbolting them from the cylinder head — there are typically 8 to 12 bolts per cover depending on engine size. Carefully pry the covers away using a gasket scraper, taking care not to gouge the aluminum sealing surface. Remove and discard the old gaskets.

Locate the AFM solenoids on top of the engine. On a 6.6L Duramax, there are typically four solenoids (one per bank, controlling two cylinders each). Each solenoid is held in place by a single bolt and has an electrical connector. Disconnect the electrical connectors first, then remove the mounting bolt. The solenoid will lift straight out.

Install the delete brackets in the solenoid mounting holes. These brackets are solid pieces of metal that fill the space where the solenoid was, preventing oil from leaking out of the hole. Bolt the brackets down finger-tight first, then torque them to the specification listed in your kit documentation — typically 15 to 25 foot-pounds. Install new valve cover gaskets, reinstall the valve covers, and torque the cover bolts in a crisscross pattern to the engine manufacturer's specification (usually 10 to 15 foot-pounds).

Reprogramming the Engine Control Module

Once the hardware is installed, you must reprogram the ECM so the engine no longer attempts to set up the solenoids. Connect your tuning device to the OBD-II diagnostic port, which is located under the steering column on the driver's side of the vehicle. The port is a 16-pin connector — your tuning device will have a cable that plugs directly into it.

Follow the tuning software's instructions to read the current ECM tune file from your vehicle. This creates a backup of your factory programming. The kit will include a modified tune file designed for your specific engine and model year. Load this file into the tuning software and flash it to the ECM. The process typically takes 10 to 20 minutes. The vehicle may restart several times during the flash — do not disconnect the tuning device or turn off the ignition during this process.

Once the flash is complete, disconnect the tuning device and start the engine. The engine should run normally on all cylinders. Check for any warning lights on the dashboard. Some tune files are designed to prevent check engine lights; others may trigger a code related to the missing solenoid. If a code appears and you did not expect it, consult the kit documentation or the tuner's support to determine whether the code is normal or indicates a problem.

What Happens After Installation

Your engine will no longer cycle between 4-cylinder and 8-cylinder operation. This means fuel economy will likely decrease slightly under light-load driving, since the engine is always running on all eight cylinders. However, many users report improved throttle response and smoother power delivery, since the engine is not constantly switching between modes.

The modification is visible to a diagnostic scan tool. If you take the vehicle to a dealership or emissions testing facility, technicians will see that the AFM solenoids are missing and the ECM has been modified. This may affect warranty coverage for engine-related repairs. Some states require emissions testing; removing the AFM system may cause your vehicle to fail inspection depending on local regulations and the specific tune file used.

If you ever need to restore the vehicle to factory condition, you will need to reinstall the AFM solenoids and reflash the original factory tune file. The solenoids themselves are not included in the delete kit and must be purchased separately from a GM dealer or parts supplier.

Common Installation Mistakes to Avoid

Do not reuse old valve cover gaskets. They compress and tear during removal, and reusing them will cause oil leaks. Always install new gaskets when you reinstall the covers.

Do not skip the battery disconnect step. Disconnecting the negative terminal prevents electrical damage to the ECM during the solenoid removal and protects you from accidental short circuits while working on the engine.

Do not interrupt the ECM flash process. If the tuning device loses connection to the vehicle during the flash, the ECM may be left in an incomplete state and the vehicle may not start. Always may support the tuning device is fully charged and the vehicle battery is in good condition before beginning the flash.

Do not assume all tune files are the same. Different tuners and kit manufacturers produce different tune files. Some are designed to prevent check engine lights; others are not. Read the documentation carefully to understand what to expect after installation.

Frequently Asked Questions

Will the AFM delete kit damage my engine?

No. The AFM system is a fuel management feature, not a structural part of the engine. Removing it does not affect engine durability or reliability. The engine will straightforward run on all cylinders all the time instead of cycling between modes. Many diesel engines run this way from the factory without any issues.

Can I reverse the AFM delete if I change my mind?

Yes, but it requires purchasing replacement solenoids from a GM dealer and reflashing the original factory tune file. The solenoids are not included in the delete kit. The process is the reverse of installation: remove the delete brackets, install the new solenoids, and reprogram the ECM with the factory tune.

Will this cause a check engine light?

It depends on the tune file. Some tune files are specifically designed to prevent diagnostic trouble codes related to the missing solenoids. Others will trigger a code. Check the kit documentation to see what the manufacturer expects. If a code appears unexpectedly, contact the tuner's support team.

Does the AFM delete kit void my warranty?

It may. General Motors and other manufacturers typically do not cover engine repairs on vehicles with modified ECM tunes or removed emissions equipment. Check your vehicle's warranty documentation or contact your dealer to understand how this modification affects your specific coverage.

Is the AFM delete legal?

Legality varies by location. Some states and jurisdictions prohibit modifications to emissions equipment or engine control systems. Others have no restrictions. Check your local regulations and emissions testing requirements before installing the kit. If your vehicle is subject to emissions testing, the modification may cause it to fail inspection.