Chevrolet Silverado 1500 2007-2018 4.3L V6 / 5.3L / 6.0L V8 AFM/DFM Disabler

A plug-in cylinder-deactivation disabler for the 2007–2018 Chevrolet Silverado 1500. It goes into the OBD-II diagnostic port and keeps the factory Active Fuel Management system from engaging, so the engine runs on every cylinder all the time. It does not rewrite engine software, and removal takes seconds: unplug the module and the vehicle is back to stock behavior.

Fitment by year and engine

The fitment table for this part (all rows marked 100% fitment match):

• 2007–2013 Chevrolet Silverado 1500: 5.3L V8 / 6.0L V8
• 2014–2018 Chevrolet Silverado 1500: 4.3L V6 / 5.3L V8 / 6.0L V8

For reference, these are the AFM-equipped GM engine codes that match the years and displacements above:

• LY5 (5.3L, 2007–2009, VIN 8th digit "J")
• LC9 (5.3L, 2007–2011, VIN 8th digit "3")
• LMG (5.3L, 2007–2014, VIN 8th digit "0")
• L76 (6.0L, 2007–2009, VIN 8th digit "Y")
• LFA (6.0L, 2008–2009, VIN 8th digit "5")
• LZ1 (6.0L, 2010–2013, VIN 8th digit "J")
• LV3 (4.3L, 2014–2018)
• L83 (5.3L, 2014–2018, VIN 8th digit "C")

In the same trucks and SUVs, GM also built V8s without AFM, for example the 5.3L LH9 (2010–2012 trucks, VIN code P), the 6.0L LY6 and L96 and the 6.2L L9H. Those engines never deactivate cylinders, so the module has nothing to manage on them. Check your code against both lists before you buy.

An engine code that is not listed here does not automatically rule the vehicle out, but send us the VIN first so we can check.

How Active Fuel Management operates

On AFM V8 engines, the computer shuts off fuel and holds the valves closed on cylinders 1, 7, 6 and 4 when the load is light, so the engine runs as a V4. It does this through special collapsible lifters on those cylinders, fed by oil-pressure solenoids. When you ask for more power, the lifters lock again and all eight cylinders fire. GM describes this behavior in its service bulletin on AFM and DFM operation.

GM's 4.3L V6 (RPO LV3) uses the same idea on two cylinders: cylinders 3 and 6 are deactivated at light load, so the engine runs on four. On V8s, AFM drops cylinders 1, 7, 6 and 4. In both cases oil-pressure solenoids switch special lifters into a collapsed state and fuel to those cylinders is cut.

For the 2019 redesign of the Silverado 1500 and Sierra 1500, GM introduced Dynamic Fuel Management on the 5.3L L84 and 6.2L L87, which can run on 17 different cylinder patterns. That is a different system from the AFM covered by this listing.

The first drive

Expect steadier behavior at part throttle and no change at wide-open throttle. Towing and hill climbing were already mostly done on all cylinders, so the biggest change is during relaxed cruising. Average fuel economy may drop slightly depending on how much of your driving is light-load highway time.

Check the engine first

Scan for stored codes before you plug it in. Misfire codes on the deactivation cylinders, an AFM solenoid circuit code, or a lifter noise are signs of an existing problem that should be repaired first. The module is meant for a healthy engine where you simply do not want cylinder deactivation.

How this differs from an AFM delete kit

There are three common ways to stop cylinder deactivation on GM engines: a plug-in module like this one, a custom tune that turns AFM off in the engine computer, or a mechanical delete that replaces the AFM lifters and related hardware and then needs a tune to match. The module is the only one of the three that needs no tools and no engine-computer changes, and it is the only one you can undo by unplugging it. It does not replace failed lifters; if hardware is already damaged, the repair comes first.

Living with it

Leave it in the port for everyday driving. When the vehicle goes in for service or an emissions check, remove it so the shop has normal access to the diagnostic connector, then reinstall it.

Why owners disable it

Many drivers would rather have predictable response than the small economy gain from running on fewer cylinders, especially when towing, hauling or driving in hills. Keeping AFM off removes the mode changes entirely. It does not add horsepower, and it is not a fix for an engine that already has lifter or oil-consumption problems.

Oil and maintenance

AFM lifters and the solenoids that control them run on engine oil pressure. Keeping the oil at the right level, using the grade GM specifies on the oil filler cap or in the owner's manual, and changing it on schedule matters whether or not AFM is active. The module changes when cylinders deactivate; it does not change the oiling system.

How to confirm your engine code

• Your model year, model and engine match a row in the table (2007–2018 Chevrolet Silverado 1500).
• The quickest checks are the 8th digit of your VIN, which identifies the engine, and the RPO list on the Service Parts Identification label (glovebox or trunk on most pre-2018 GM models, QR code on the driver-door pillar label from 2018).
• No check-engine light is on, and oil level and pressure are normal.
• If the vehicle has an engine swap, an aftermarket tune or a replacement engine computer, contact support first.
• Questions: support@automotivebypass.com with your VIN.

Shipping and support

Standard shipping inside the lower 48 states costs nothing; allow 1–2 business days of handling plus 3–4 in transit. Returns need approval first and must be requested within 45 days. Approved returns are subject to a 20% restocking fee, with return shipping paid by the customer. A 3-year limited warranty applies. Email support@automotivebypass.com (Mon–Fri, 9–5 PST) with your VIN if you want a fitment check.