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What Is Cylinder Deactivation?

In the neverending search for better fuel efficiency, many manufacturers have implemented a system called Cylinder Deactivation (CD). It can go by many names, depending on the manufacturer. This system is frequently found in modern vehicles with large displacement engines, such as pickup trucks and full size SUV's.

What Does It Do?

CD is a process that involves shutting down multiple cylinders while an engine is running under light load situations in order to improve fuel economy. By design, the computer always shuts down the same cylinders and does not cycle through them in any way.

 

How Do I Know If I Have This System?

If your vehicle is equipped with CD, you will likely feel a loss of power while at cruising speed. When giving the engine more throttle, you will feel it increase back to normal as the other cylinders are reactivated.

 

Is This Something I Should Be Worried About?

If you plan on keeping your vehicle long term, absolutely. 

 

What's The Big Problem?

As mentioned before, CD always deactivates the same designated cylinders when it is active. Let's use a GM 5.3L V8 with Active Fuel Management (AFM) as an example. AFM will cut off 4 cylinders during light load situations, thus increasing MPG by not utilizing all 8 cylinders. The problem that surfaces with this idea is the deactivated cylinders do not get enough lubrication to keep them running optimally. This means increased wear and tear on those parts of the engine, which is especially bad since they are essentially being stopped and started over and over again as throttle use fluctuates via user input. Premature failure of lifters, camshafts, and more have been attributed to AFM Technology.

 

Can I Turn The System Off?

From the factory, no. However, issues with CD have become so prevalent that many people take their vehicle to a trusted mechanic to have their CD system deleted. It should be noted that dealerships do not offer this service and could (most likely will) void your engine warranty if you have any remaining.

Using AFM as an example again, the following engine components will need to be replaced:

  • The 4 AFM lifters
  • The AFM camshaft
  • The ECU will need to be re-tuned

Depending on your location, this work typically runs anywhere from $2500 - $3500 parts and labor. This IS NOT a do it yourself project, even for a seasoned DIY mechanic. You must open up the engine and extreme care must be taken to not damage other internal engine components. In addition, tuning for the new parts must be completed by a professional mechanic, preferably with a dyno.

 

I Don't Want To Open Up My Engine. Is There Any Other Way?

Possibly. Recently some software companies have released OBD-II (On Board Diagnostics 2.0) compatible plug-in solutions that can disable the CD system by reprogramming the software coding inside the ECU. In theory, this allows the engine to run as it normally would if CD was never installed. These devices are somewhat new, so it is advisable to research the kit you are looking at to see if it has worked for others. These are FAR cheaper than going for the "official" delete option, but obviously are not as guaranteed to work as physically removing the CD hardware.

 

Is There Anything Else I Need To Be Aware Of?

Not really. Countless vehicles have had their CD systems deleted and gone on to live long, healthy, high mileage lives. If the work is performed by a reputable mechanic, you should never have to worry about having any CD-related issues again. 

 

 

Video overview of how cylinder deactivation works:

 

by Roadshow

 

by Engineering Explained

Awesome! You tha man.

Nice write-up!

Fantastic!

17 Answers
2

Cylinder deactivation applications

 

The following automakers have used (and continue to use) cylinder deactivation in some of their lineups.  Below is a list of the car brands (in alphabetical order) along with their branded name for the technology:

  • Acura:  Variable Cylinder Management (VCM)
  • Alpha Romeo:  uses cylinder deactivation (no branded name available)
  • Aston Martin:  uses cylinder deactivation (no branded name available)
  • Audi:  Cylinder On Demand (COD)
  • Bentley:  uses cylinder deactivation (no branded name available)
  • Buick, Cadillac, Chevrolet, GMC: Displacement on Demand (DOD) or Active Fuel Management (AFM); later succeeded by Dynamic Fuel Management (DFM)
  • Chrysler:  Multi-Displacement System (MDS)
  • Dodge:  Multi-Displacement System (MDS)
  • Ford:  earlier versions had no name, some later versions were branded Variable Displacement Engine (VDE)
  • GMC:  Active Fuel Management;  later succeeded by Dynamic Fuel Management (DFM)
  • Honda:  Variable Cylinder Management (VCM)
  • Jeep:  Multi-Displacement System (MDS)
  • Koenigsegg: uses cylinder deactivation (no official name)
  • Lamborghini:  Cylinder Deactivation System (CDS)
  • Mazda:  uses cylinder deactivation (no branded name available)
  • Mercedes-Benz:  Active Cylinder Control (ACC);  later succeeded by Cylinder Management System (CMS)
  • Porsche:  uses cylinder deactivation and sometimes referenced as adaptive cylinder control (but not officially branded)
  • Ram:  Multi-Displacement System (MDS)
  • Volkswagen:  Active Cylinder Technology (ACT) or Active Cylinder Management (ACM)

To date, the following automakers have not implemented cylinder deactivation in their engines:

  • BMW
  • Bugatti
  • Ferrari
  • Fiat
  • Genesis
  • Hyundai
  • Infiniti
  • Jaguar
  • Kia
  • Land Rover
  • Lexus
  • Lincoln
  • Maserati
  • McLaren
  • Mini
  • Mitsubishi
  • Nissan
  • Pagani
  • Rolls-Royce
  • Subaru
  • Toyota
  • Volvo

This site is going to be the Library of Alexandria of cars.

2

Acura/Honda

Variable Cylinder Management (VCM)

 

In the previous section we listed the automakers that use cylinder deactivation and the corresponding nomenclature each uses to market the technology.  Now we go over how the automakers’ version of the technology works below.

 

https://en.m.wikipedia.org/wiki/Variable_Cylinder_Management

VCM Videos (2):

2

Audi:  Cylinder on Demand (COD)

COD Articles (2):

https://www.audi-technology-portal.de/en/drivetrain/engine-efficiency-technologies/4.0-tfsi-engine-with-cylinder-on-demand-en

https://www.greencarcongress.com/2013/11/20131113-audi.html

 

COD Videos (3):

2

Bentley:  Cylinder Deactivation (no official marketing name)

 

 

Articles:

1

Mazda

Cylinder Deactivation under SkyActiv-G (no official marketing name)

Articles

 

Videos

1
Mercedes-Benz:

Active Cylinder Control (ACC);  later replaced by Cylinder Management System (CMS)

Articles

 

Videos

1

Porsche:  Cylinder Deactivation sometimes called Adaptive Cylinder Control (ACC)

Articles (2):

(1) https://newsroom.porsche.com/en/company/porsche-new-v8-petrol-engines-dynamic-efficiency-12694.html

(2) https://newsroom.porsche.com/en/press-kits/718-spyder-cayman-gt4/motor-und-performance.html

 

Video:

https://m.youtube.com/watch?v=s3qbFVoVYyc

1

Volkswagen:  Active Cylinder Technology (ACT) or Active Cylinder Management (ACM)

Article:

https://www.autoblog.com/2011/09/08/volkswagen-details-worlds-first-4-cylinder-engine-with-cylinder/

 

Videos (3):

https://m.youtube.com/watch?v=yxjGTBF-dVY

https://m.youtube.com/watch?v=yoohR8sar5g

https://m.youtube.com/watch?v=DJ4eLGVLXXw

1

(Add the following post between Ford and Mazda)

Koenigsegg: Cylinder Deactivation under Freevalve (no official marketing name)

Articles (2):

(1)  https://www.caranddriver.com/news/a15349580/koenigseggs-camshaft-less-engine-explained-watch-it-in-action-video/

(2) https://www.roadandtrack.com/new-cars/car-technology/a31451281/koenigsegg-gemera-engine-specs-analysis/

Videos (2):

(Scroll to 5:05 in Engineering Explained video)

https://m.youtube.com/watch?v=WwlNqaz9q_0

 

https://m.youtube.com/watch?v=OZWeNPi2XkE

0

Which year, make, and models have cylinder deactivation?

Below for each automaker (in alphabetical order) we list the years, models, and engines that have cylinder deactivation.  While much effort was made to capture all years/models/engines with accuracy, it is a good idea to cross-check with the brochure (for that year and model) when shopping for a vehicle - you can Google the brochure and download it, and that information is usually mentioned there under the company’s branded name for that technology.

 

Acura:  Variable Cylinder Management (VCM)

MDX:

MY 2014-2020 (3rd Gen YD3)

- 3.5L V6
- 3.0L V6 Hybrid

MY 2022-   (4th Gen YD4)
- 3.5L V6

RDX:

MY 2013-2018 (2nd Gen TB3/4)
- 3.5L V6

RLX:

MY 2014-2020  (only generation KC1/2)
- 3.5L V6
- 3.5L V6 Sport Hybrid

TLX:

MY 2015-2020 (1st Gen UB1/2)
- 3.5L V6

0

Alpha Romeo:  Cylinder Deactivation (no marketing name)

Giulia:

MY 2017-
- 2.9L twin-turbo V6

Stelvio:

MY 2018-
- 2.9L twin-turbo V6

0

Aston Martin:  Cylinder Deactivation (no marketing name)

DB11:

MY 2017-
- 4.0L twin-turbo V8
- 5.2L twin-turbo V12

DBS Superleggera:

MY 2018-
- 5.2L twin-turbo V12

DBX:

MY 2021-
- 4.0L twin-turbo V8

Vantage:

MY 2018-
- 4.0L twin-turbo V8

0

Audi:  Cylinder on Demand (COD)

A8/A8 L:

MY 2013-2018 (3rd Gen D4, Type 4H)
- 4.0L twin-turbo V8

MY 2015-2016 (3rd Gen D4, Type 4H)
- 6.3L W12

MY 2020-present (4th Gen D5, Type 4N)
- 4.0L twin-turbo V8

R8:

MY 2017-present (2rd Gen Type 4S)
- 5.2L V10

RS 6:

MY 2021-present (Gen C8, Type 5G)
- 4.0L twin-turbo V8

RS 7:

MY 2014-2018 (1st Gen, Type 4G8)
- 4.0L twin-turbo V8

MY 2021-present (2nd Gen, Type 4K8)
- 4.0L twin-turbo V8

RS Q8:

MY 2020-present
- 4.0L twin-turbo V8

SQ7:

MY 2020-present (2nd Gen, Type 4M)
- 4.0L twin-turbo V8

SQ8:

MY 2020-present
- 4.0L twin-turbo V8

S6:

MY 2013-2018 (Gen C7, Type 4G)
- 4.0L twin-turbo V8

S7:

MY 2013-2018 (1st Gen, Type 4G8)
- 4.0L twin-turbo V8

S8:

MY 2013-2018 (3rd Gen D4, Type 4H)
- 4.0L twin-turbo V8

MY 2020-present (4rd Gen D5, Type 4N)
- 4.0L twin-turbo V8

0

Bentley:  Cylinder Deactivation (no official marketing name)

Bentayga:

MY 2017-present

  • 6.0L turbo-charged W12

MY 2019-present

  • 4.0L turbo-charged V8


Continental GT
:

MY 2013-2018 (2nd generation)

  • 4.0L turbo-charged V8

MY2016-2018 (2nd generation)

  • 6.0L turbo-charged W12

MY 2020-present (3rd generation)

  • 4.0L turbo-charged V8

MY2019-present (3rd generation)

  • 6.0L turbo-charged W12


Flying Spur
:

MY 2015-2019 (2nd generation)

  • 4.0L turbo-charged V8

MY 2016-2019 (2nd generation)

  • 6.0L turbo-charged W12

MY 2021-present (3rd generation)

  • 4.0L turbo-charged V8

MY 2020-present (3rd generation)

  • 6.0L turbo-charged W12


Mulsanne
:

MY 2012-2020

  • 6.75L turbo-charged V8
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