how to turn off active fuel management

2 min read 20-01-2025

Active Fuel Management (AFM), also known as cylinder deactivation, is a technology designed to improve fuel economy in vehicles. It works by shutting off cylinders when less power is needed, such as during cruising. However, some drivers find AFM's operation disruptive or prefer consistent engine performance. This article explains how to disable AFM, covering various methods and considerations.

Understanding Active Fuel Management (AFM)

Before diving into disabling AFM, let's understand what it is and why you might want to turn it off. AFM improves gas mileage by reducing engine load. It achieves this by deactivating certain cylinders under light-load conditions. This leads to noticeable changes in engine sound and vibration.

Some drivers dislike the rough idle or noticeable transitions that occur when the system switches between active and inactive cylinders. Others report increased engine wear over time due to the constant cycling on and off of cylinders. Finally, some believe that AFM may negatively impact engine longevity.

Methods to Disable Active Fuel Management

The method for disabling AFM varies depending on your vehicle's make, model, and year. There are three main approaches:

1. Using the Vehicle's Settings

Some newer vehicles offer a built-in setting to disable AFM. Check your owner's manual for instructions. The setting might be labeled as "AFM Off," "Cylinder Deactivation Off," or something similar. It's usually located within the vehicle's infotainment system or a dedicated settings menu.

Where to Find it: The location will vary greatly; consult your owner's manual. It might be in the settings menu under "Engine," "Powertrain," or "Vehicle Settings."

2. Through a Performance Tuner or Programmer

Performance tuners or programmers can modify your vehicle's engine control unit (ECU). This allows for more extensive control over various engine parameters, including AFM. These devices are available from various aftermarket manufacturers.

Important Considerations: This approach often requires technical expertise. Incorrect programming can damage your vehicle's engine. Only use reputable tuners from trusted brands.

3. Mechanical Modifications (Generally Not Recommended)

While possible, physically disabling AFM through mechanical modifications is generally not recommended. This usually involves altering or removing parts of the AFM system, which can void your warranty and potentially damage your engine. This should only be undertaken by experienced mechanics.

Frequently Asked Questions (FAQs)

Q: Will turning off AFM improve performance?

A: You might experience a slightly smoother idle and more consistent power delivery, but the performance gains are usually minimal.

Q: Will turning off AFM reduce fuel economy?

A: Yes, disabling AFM will likely decrease your fuel economy, as the system is designed to improve it.

Q: Is it safe to disable AFM?

A: Disabling AFM through the vehicle's settings or a reputable tuner is generally safe. However, mechanical modifications carry significant risks.

Q: Will disabling AFM void my warranty?

A: Disabling AFM through the vehicle's settings typically won't void your warranty. However, modifications using tuners or mechanical alterations often will.

Conclusion: Weighing the Pros and Cons

Disabling Active Fuel Management offers potential benefits for some drivers, such as a smoother engine operation. However, it comes at the cost of reduced fuel economy. Before making any changes, carefully consider your priorities and consult your owner's manual or a qualified mechanic. Choosing the right method—using in-vehicle settings if available—is the safest and easiest route. Remember to always prioritize safety and avoid modifications that could potentially damage your vehicle.