How to Disable AFM without a Tune?

No doubt, the active fuel management (AFM) system is one of GM’s technologies that distinguish the brand in the automotive industry. Of course, people want vehicles with improved gas mileage.

Hence, the AFM system makes GM’s Chevy a perfect car for such a purpose. However, the system comes with a couple of drawbacks that make a lot of users think twice.

Reason enough, some Chevy owners consider deleting or disabling the AFM system to be the way out. First of all, let’s see how the system works, it’s a major problem, and then finding how to disable AFM without a tune will be easier.

How does AFM System Works?

The idea behind the active fuel management (AFM) system is to minimize fuel consumption rate without altering the normal overall performance of an AFM-equipped vehicle.

Therefore, GM designed this system to enable V8 engine users to step down to V4 when the vehicle does not require much power.

So, the active fuel management system is activated to reduce fuel consumption by using half of the cylinders in an AFM-equipped engine. This is usually during less-power demanding driving like cruising on the highway.

Meanwhile, the system automatically reactivates the other idle cylinders and gets them back to work in delivering more engine power in a driving situation that requires more acceleration, ascending a hill, or towing loads.

Therefore, the AFM system utilizes a synergized operation between sophisticated software and hydraulic valves to deactivate half of the vehicle’s cylinder when driving does not require full engine power.

For instance, the system will deactivate four cylinders in an eight-cylinder engine to utilize the other active four and reactivate the idle or deactivated four cylinders once it senses a demand for more power for performance.

It is the same for a six-cylinder engine, whereby the AFM deactivates three of the cylinders and works with the other active three, and reactivates the idle three cylinders once the driver needs full power for acceleration, towing, etc.

The active fuel management operation engages special valve lifters in place of the deactivated cylinders. It also utilizes the advanced engine control module, manifold assembly, and lifter oil for its operations.

However, there’s a challenge that is peculiar to the AFM operation in a vehicle. Most GM enthusiasts complain about the switching Chevy 8 cylinder to 4 cylinder problems, especially the AFM lifter failure. This is a major reason why users prefer to delete AFM or disable its operation.

how to disable afm for free

AFM Lifter Failure Symptoms

Although the active fuel management operation plays a vital role in ensuring a better fuel economy, its impacts on the other hand, can be detrimental to the AFM lifter. 

The regular deactivation and reactivation of half of the cylinders in the vehicle can result in the AFM lifter failure when you least expect it. This is immediately followed by a couple of symptoms. Some of the AFM failure symptoms include:

Low engine power

Since the AFM works by disengaging some cylinders and reactivating the same, it minimizes the pressure on the engine and suddenly puts more pressure when more power is needed.

Constantly engaging this process can affect engine power over time. So, if you discover that your car’s engine operates at low power levels, you most likely have an AFM lifter failure.

Downshifting difficulty

Again, the transmission system is engaged in the AFM operations, hence, the tendency to experience a transmission system issue. Usually, the problem is with the downshifting operation, as you may experience difficulty in this area.

Hesitation during acceleration

Although there are other faults that can cause a vehicle to hesitate during acceleration, an AFM lifter failure may not be entirely blameless in some cases. So, you may want to check that out if you’re experiencing this challenge at the moment.

Engine stalling

Also, although engine stalling can be traceable to different causes like an empty gas tank, bad fuel pump, low fuel pressure, etc., however, the AFM lifter failure can also be a culprit for AFM-equipped vehicles.

Check Engine light display

Of course, any malfunction that tampers with the normal operations of a vehicle’s engine is just a “blink of an eye” away from illuminating the Check Engine light. So, this is yet another of the numerous 5.3 lifter failure symptoms you may encounter.

What Causes Lifter Failure?

Identifying the causes of lifter failure can help you avert its occurrence at any time. This will save you the stress (energy) and money that fixing the component will demand. So, some of the causes of AFM lifter failure include the following.

Wear and tear

Virtually all vehicle components are susceptible to wear and tear through constant usage over time. For instance, the active fuel management operation engages and disengages several internal mechanisms over and again. Consequently, this can cause increased wear and tear.

 So, failure to engage in regular maintenance can result in the damage of various components and eventually lead to the AFM lifter failure.

Poor oil quality

Oil plays a vital role in a vehicle’s engine operations. However, using the recommended oil for your car is a necessity. Therefore, using engine oil with poor quality can pose a serious threat to the engine and eventually result in damage to the AFM lifter.

Low oil levels

Running on low oil levels is an experience you must avoid at all costs. This is because some components, including the AFM lifter, require adequate lubrication to function optimally. 

Therefore, running on low oil levels will result in friction between the engine’s moving parts, and this can collapse the AFM lifter.

How Do I Prevent AFM Lifter Failure?

Irrespective of the tendencies for AFM lifter failure to occur, there are a few measures that can help you prevent the problem from surfacing in the first place. Some of the measures on how to prevent AFM lifter failure include the following.

Regular vehicle maintenance

A regular vehicle maintenance culture can help to prevent several problems, including an AFM lifter failure. Therefore, ensure to design a routine for your car servicing.

An expert auto technician can advise you on the interval and help you perform this exercise regularly. With this habit, you can be sure of averting a sudden AFM lifter failure in your car.

High-quality oil usage

Remember that low oil quality is a culprit to AFM lifter failure. In that case, it is advisable to use the best and most suitable oil for your vehicle in order to prevent the occurrence of AFM lifter failure.

Meanwhile, ensure to consult your car’s manufacturer’s manual or an expert auto mechanic for details on the type of oil you need.

Disable AFM system

Since the active fuel management operation is a threat to the AFM lifter, it is only ideal to disable the system in order to avoid damage.

When you disable the AFM system, it reduces the tendency for AFM lifter failure since the system doesn’t have to work constantly. Some people even go as far as deleting the AFM completely.

How to Disable AFM without a Tune

The AFM system is quite easy to disable. All you simply need is to either trick or reprogram the vehicle’s Electronic Control Unit (ECU) to remain in V8 mode constantly. Now, let’s see how to disable AFM without a tune.

Get an AFM disabler

An AFM disabler is the solution to tricking the ECU to enable the system to remain in V8 mode at all times. The Range Technology AFM disabler is an ideal device for this purpose. It is designed to only suspend the AFM’s operation and keep the engine in V8 mode without voiding the warranty.

It is important to note that reprogramming the Electronic Control Unit can void your car’s warranty. This is why using the Range Technology AFM disabler is ideal for your car.

Plug the disabler to the OBD II port

Once you get the AFM disabler, simply locate the OBD II port beneath the dashboard at the driver’s side and plug it in. Once you plug in the device, it will start work immediately by keeping the vehicle on V8 mode perpetually until you unplug it.

So, you can unplug the device whenever you need to see your dealer and still have the car intact without voiding the engine’s warranty.

The disabler is designed in different colors, which gives you several options to choose from as it suits your desire. However, the colors have nothing to do with the disabler’s function. They are simply the same irrespective of the difference in the LED light display (color).

How to Delete or Disable Active Fuel Management (AFM)

Deleting the active fuel management operation is another option to help curb the challenge of the AFM system. This can cover up for AFM lifter failure as well if you’re experiencing a repeat in AFM lifter failure. Now, let’s see how to delete the active fuel management (AFM) system.

Install an AFM system delete kit

You need a couple of parts replacement when deleting the AFM system. This is usually ideal if the AFM lifter fails. Some of the operations include replacing the vehicle’s cam with a non-AFM camshaft and changing the existing AFM lifters with their standard lifters counterparts.

The process also needs a valve cover replacement with a non-AFM flat valve cover. Then, plug the system’s pressure relief valve into the oil pan, and replace the high-volume engine oil pump with a standard or normal oil pump.

The AFM delete kit installation process is both money and time-consuming. In fact, this is rarely a DIYer’s operation. So, you will need to budget for purchasing all the components outlined above and the labor cost.

In that case, it would be best to opt for a Range Technology AFM disabler to help you disable the active fuel management (AFM) system’s operation. This will also help you avoid any problems after disabling the AFM.


How do I bypass active fuel management?

The active fuel management (AFM) system can be suspended from its regular operation by installing an AFM disabler. This device is designed to trick the vehicle’s ECU into keeping the engine on V8 mode perpetually.

Therefore, the AFM operation will be suspended to enable the engine to operate without half of the cylinders shutting up to reduce performance and improve gas mileage. This is an ideal solution if you’re currently battling the negative impacts of the AFM system’s operation.

Can AFM be turned off?

Of course, you can turn off AFM in your car. If you’re currently experiencing challenges with the AFM system, simply get a Range Technology AFM disabler and plug it into the car’s OBD II port under the dashboard at the driver’s side.

Once you install the device, it will turn off the AFM system’s operation immediately and keep the engine in V8 mode constantly. In that case, you won’t have to operate on V8 and V4 back and forth until you unplug the disabler.

Can you disable AFM with a programmer?

Yes, you can disable your car’s active fuel management system with an AFM delete programmer. The software is designed to reprogram the electronic control unit and sustain the engine in V8 mode without moving back and forth from V8 to V4.

However, reprogramming your car’s ECU to disable the AFM system’s operation will eventually void the engine’s warranty.

Therefore, applying another approach (installing an AFM disabler) is best because of the vehicle’s engine warranty. You can always unplug the disabler at any time before seeing your dealer.

Is it safe to disable Active Fuel Management?

Yes, it is completely safe to disable the active fuel management (AFM) system’s operation in a car. Besides the reduced fuel consumption, the AFM operation causes more harm than good. It can damage the AFM lifter and other components before you know it.

So, it is advisable to disable or delete the AFM operation and keep your car’s engine in V8 mode constantly. However, it may reverse the car’s fuel economy to standard consumption since the system no longer switches between V8 and V4.

Will disabling AFM void the warranty?

No! Disabling your car’s AFM will not void the engine warranty if you’re contemplating, “Should I disable AFM?” However, it depends on the option you implement. If you reprogram the car’s electronic control unit, it can void the warranty.

Meanwhile, installing the Range Technology AFM disabler will stop the AFM’s operation and still retain the engine warranty.

So, if you are fed up with the active fuel management operation in your car, kindly get an AFM disabler to end the system’s operation as soon as possible. This will surely give you peace of mind.

Final Words

Understanding how to disable AFM without a tune is pretty straightforward. This has been proven in this article. So, you don’t have to panic or carry the regret of buying a car that is fitted with an active fuel management operation.

Most GM car owners have reduced the AFM failure rate by installing the Range Technology AFM disabler.

You too can save yourself the stress of worrying about the negative impacts of the AFM system in your car by using the AFM disabler. This approach is much more preferable than implementing a 5.3 active fuel management delete on your Vortec engine.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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