How to Tell if a Vehicle has Active Fuel Management

The technology Active Fuel Management (AFM) is used to make vehicles more fuel efficient. This system is typically available in V6 and V8 engines. The AFM switches off half of the engine’s cylinder when not required high power.

The switch on and off is a highly complex process and that’s why the AFM is considered to be the most complicated system added to a vehicle. The AFM has many advantages; therefore, General Motors widely uses it in their vehicles.

However, the AFM system has some problems, too. Therefore, some drivers delete or try to avoid the Active Fuel Management system. If you own a used or new vehicle and want to know if it has an AFM system installed, keep reading.

The easiest way to tell whether a vehicle has AFM or not is by looking at the digital screen from the driver’s seat. In GM vehicles, this digital screen is known as the Driver Information Center or DIC.

The information center shows whether the AFM is in operation or not.

v4 indicator

Some vehicles also display “Eco” instead of V4/V8, which also indicates that the vehicle has an Active Fuel Management system. If the vehicle has AFM system installed but the dashboard displays V8 mode, then maintain a cruise speed under 2,000 RPM mark, the system automatically switches to V4 mode.

This process will make clear that the vehicle’s Active Fuel Management system is in operation. Another easy way is to check the vehicle owner’s manual.

If the owner’s manual is available, follow the steps to determine AFM availability in your vehicle:

  • Go to the engine specification section
  • Check the bullet points that mention AFM, fuel-saving features, or cylinder deactivation system.
  • It should be available in the owner’s manual if the AFM system is available in your vehicle.

Some vehicles come with AFM logo, which helps to tell whether a vehicle has Active Fuel Management. You can also ask your dealership about AFM system availability.

Watch the to learn how to tell if a vehicle has AFM or not:

You can Also Tell by Checking Components of Active Fuel Management

This is another practical way to tell whether a vehicle is equipped with Active Fuel Management or not. Look at the following components to ensure whether a vehicle has AFM or not:

  1. AFM Towers
  2. Valley Cover
  3. Notched Lifter Guides
  4. Automatic Transmission
  5. Unique Oil Lifter Guides
  6. Valley Cover Gasket
  7. High-capacity Oil Pump

Which Chevy Engines have Active Fuel Management?

Active Fuel Management System usually comes with V6 and V8 engines.

Here is the list of General Motors engines that use Active Fuel Management system:

  • 6L V6 LGX
  • 0L V6 LGW (Twin-Turbo)
  • 9L V6 LZ8
  • 9L V6
  • 3L V6 LV3
  • 2L V8 LTA
  • 3L V8 Vortec
  • 3L V8 Vortec 5300
  • 3L V8 L83
  • 3L V8 LS4
  • 2L V8 L86
  • 2L V8 LT1
  • 2L V8 LT4
  • 2L V8 L99

What Vehicles have Active Fuel Management?

Chevy vehicles use the Active Fuel Management system to improve their fuel efficiency.

The following GM vehicles under the Chevrolet brand come with AFM:

  • Chevrolet Silverado
  • Chevrolet Impala
  • Chevrolet Camaro
  • Chevrolet Avalanche
  • Chevrolet Tahoe
  • Chevrolet Suburban
  • Chevrolet TrailBlazer

However, General Motors also uses AFM in their other vehicles like Cadillacs and a few others.

AFM Pros and Cons

The main advantage of Active Fuel Management system is to improve fuel economy. When not needed, an operational AFM deactivates half of the engine’s cylinders and improves fuel economy by 5% to 10%.

On the other hand, Active Fuel Management has some disadvantages, too. An engine with an AFM system contains more complex components compared to conventional engines.

Therefore, the chances of wearing out, failing, or problems will increase. A properly operational AFM simply improves vehicle’s fuel efficiency. But when it starts to fail, it causes much more problems.

Faulty AFM causes the engine to start jerking or hesitating when accelerating, reduces engine power, and is suddenly stuck. A faulty AFM system increases fuel consumption, too.

How to Delete or Disable Active Fuel Management?

Active Fuel Management is not a completely reliable technology yet. When it fails, several issues, such as noisy lifters, high fuel consumption, and engine problems, occur. In this case, you want to disable the Active Fuel Management.

The problems become more severe when a vehicle is not maintained correctly. You can easily disable Active Fuel Management by using AFM disabler device. Connect the AFM disabler to the OBD-II port and follow the instructions mentioned on the device to disable the AFM system.

This will disable the AFM system, and it is completely reversible process. Whenever you want, you can reactivate the AFM system. However, the AFM disabler will not work all the time.

If the vehicle already has high fuel consumption and lifter noise issues, AFM disabler cannot fix it properly. To fix this issue, you need to replace some AFM components with standard ones.


What cylinders have AFM lifters?

AFM lifters use different cylinders to switch off or deactivate the cylinders and reduce fuel consumption. For V8 engines, AFM lifters deactivate cylinder numbers 1, 7, 4, 6.

In contrast, for V6 engines, AFM lifers deactivates cylinder numbers 3 and 6. However, cylinder deactivation for LT2 and LTA engines occurs on 2, 3, 8, and 5 number cylinders.

Why do GM AFM lifters fail?

Several problems are responsible for GM AFM lifters failing, including:

  • Contaminated fuel
  • Inappropriate oil pressure
  • low oil levels
  • quick acceleration and deacceleration
  • worn oil pump
  • internal component failure

Always use high-quality engine oil and check oil levels regularly to keep the AFM lifters healthy.

Does AFM cause engine damage?

A properly working AFM is perfect for an engine. It will improve the fuel efficiency and ensure smooth engine operation. But when AFM fails, it causes many problems including oil contamination or sludge.

The oil contamination damages the camshaft and lifter badly, and sometimes they become irreparable. Ultimately, all these problems damage the vehicle’s engine.

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