I recently bought a Honda Civic that had this in the car:

enter image description here

I have no idea what it does, and how it's supposed to help. Even Honda's website is ambiguous, just using a lot of fuzzy words to describe what it does. From the website:

Econ Button and Eco Assist™ System

With the exception of the Si models, all Civics are equipped with the Econ Button™ to help enhance your fuel efficiency while driving. The Ecological Drive Assist System (Eco Assist™) is a fuel efficiency information system designed to help you develop and maintain a fuel-efficient driving style. The system monitors driving style, and can display the impact of your driving style on the vehicle’s fuel efficiency. This feedback can help you make adjustments to take full advantage of the fuel efficiency potential of the Civic.

Is it some sort of placebo effect? It says it's supposed to help me improve driving, in conjunction with good road habits. But what is it actually doing when I push that button?

  • 4
    Reading the page, it sounds like it does absolutely nothing to directly provide better fuel economy. It says it provides the driver with different information to help the driver make better driving decisions and thus promote better fuel economy. IMHO, exactly like you said, a placebo. Commented Oct 16, 2014 at 17:39
  • Just thinking about this again, if you want any sure answer on this, go down to a dealership and ask a salesman about it. They are sure to give you an ear full, but you'll probably be able to squeak an answer out of them some how. Commented Oct 17, 2014 at 20:44
  • @Paulster2 The one I asked also gave the same answer, along with a bunch of useless information "use it when you drive above 50mph for guranteed increase in fuel economy", like I believe it's some sort of magic button for free miles
    – yuritsuki
    Commented Oct 17, 2014 at 21:01
  • Welllll ... I'd say test it to see if it actually does anything for you. Couple of tank-fulls with it on, a couple with it off. Keep track and report back your findings :D Best I can tell you. Maybe someone else has a better answer (Hopefully, lol). Commented Oct 17, 2014 at 21:09
  • Some hard data here since I can't post an answer. It's comparing ECON mode of a 2016 Honda Pilot being enabled vs disabled over the same 1,600 mile stretch.
    – Claus
    Commented Mar 23, 2016 at 4:58

12 Answers 12


The ECON button is not a placebo, though the wording from that specific web page is a bit vague.

The key is that the ECON button and the Eco-Assist system are two separate things.

According to Honda, pressing the ECON button configures your car to improve mileage at the cost of performance. Turning it off will improve power and reduce mileage, which you might want to do when driving in the mountains, for example.

Economy modes like this with vehicles typically work by making changes to both the engine and drivetrain to improve efficiency while reducing power.

Examples of ways to do this include changing the speed at which the automatic transmission shifts into higher gears, advancing or retarding engine timing, restricting the amount of air and fuel admitted to the engine, and in some cases even completely shutting off one or more cylinders in the engine.

In the case of the Honda Civic, I found reference to the following specific changes with ECON mode.

  • Gentler throttle: Limits how much the throttle opens when you press on the gas pedal.
  • More efficient shifting: The automatic transmission shifts into higher gears sooner, which means slower acceleration but better fuel economy
  • Reducing the length of time the air conditioner runs

Effectively this means the ECON mode limits your ability to waste gas by making it impossible to do certain wasteful things. It might be possible to achieve the same efficiency with manual driving, but it would not be easy.

The Eco-Assist system is a separate system which uses color-changing lights on your dash to help you monitor the efficiency of your driving style. Rapid acceleration, riding the brakes, and other silly driving habits will make the dash indicators blue. A more efficient driving style will cause them to glow green. The more green you see, the better your mileage will be.

  • 1
    Thanks, I edited my title to reflect my actual question. But I still don't understand what the ECON button does. Yes, I've read the description from Honda, but telling me "it does something to your car to get better mileage" isn't really helping me understand what does
    – yuritsuki
    Commented Oct 31, 2014 at 0:05
  • Edited to add some more specifics. If you want technical details of exactly how this is accomplished in the software, you'll probably need to talk to someone from Honda engineering.
    – barbecue
    Commented Nov 8, 2014 at 22:05
  • In theory, this seems nice, but are there any stats on how much this actually affects your mileage in practice?
    – Matt
    Commented Jul 6, 2015 at 21:04
  • 1
    I've not seen any published statistics on this from Honda, but since actual mileage is highly subjective anyway due to differing driving habits, terrain, and weather, I doubt that any statistics would be directly meaningful to any specific driver.
    – barbecue
    Commented Jul 9, 2015 at 22:22

I don't know what that specific button does, but I can tell you what similar buttons in other cars do: they retard your throttle response so that your car feels more sluggish. This means that when you step on the gas, it does not cause the throttle to open quite as much, making your drive smoother and more fuel efficient. Conversely, a "sport" button would increase throttle response and make for a more lively feeling car. You don't need to press the accelerator quite as far to get the car to move.

That's the simplest system. Some systems also switch off the car at a stop, shut down the fuel injection system when coasting and/or adjust the air/fuel mix to burn very lean (lean = less fuel/more air) when driving slow with little load on the engine.

In a lower powered car, the effect wouldn't be very pronounced. You would hardly notice a difference. But in higher performance cars, especially turbocharged cars, the effect can be simply astonishing. If you ever have the chance, go test drive a new BMW 320i. They have 3 modes (I think) : econ, comfort and sport (or something like that). Each mode is markedly different.

  • 1
    BMW 320D EfficientDynamics has Eco, comfort and sport. I regularly get over 73mpg (UK) / 61.03 mpg (US) 25.9482 Km/L on Eco on mine. It also changes how AirCon works and switches it off when accelerating to reduce engine load
    – Mauro
    Commented Jun 9, 2015 at 8:56
  • 2
    I know but the system works in the same way, was just adding additional information for you and confirming your statements.
    – Mauro
    Commented Jun 9, 2015 at 9:00
  • 1
    Sorry, you're right. Commented Jun 9, 2015 at 9:13

I have a 2013 Honda Civic EX Sedan. The ECON mode, from my research and personal experience with my car, does the following: changes the shift pattern of the transmission to maximize mpg by limiting downshifts unless you "floor it", reduces the A/C compressor operation and A/C fan to conserve mpg, changes the throttle response to maximize mpg and adjusts the cruise control so that when you "resume" speed it accelerates more leisurely instead of downshifting to quickly resume set speed - as far as I know, that's all it does. On my car, it seems to make very little difference.


I drive a 2014 Civic EX coupe, automatic, and about a week ago turned the Econ button off... the icon light on the dash turned off. I bought the car several months ago and it didn't occur to me until now to try this. Performance has been about the same, but my mileage has actually INCREASED 3-4 MPG! Go figure.


I've turned it on, and turned it off. I notice virtually no difference in performance or fuel economy between the 2 modes. I get consistent 37-38 mpg in either mode and the air conditioning seems to run the same in either. No difference in acceleration or any other differences. I personally think it is a placebo. It's a 2015 Civic LX.


Great page. I just bought a 2016 Honda Pilot Touring 2WD and have been playing around with the ECON button along with the Idle-Stop features. For those not familiar with the Idle-Stop feature, when the car comes to a stop, the engine automatically shuts off to conserve fuel and improve fuel economy...and the engine starts up when the brake is released.

First of all, I agree with others that the acceleration is noticeably more gradual with the ECON mode on as the computer software adjusts the engine for gentle throttle. So the decreased performance in ECON mode is real...so the question is, is the increased fuel economy real as well. So, I've tested the ECON mode on and off but with the Engine Idle Shut Down feature on and off respectively to get a bigger difference in fuel economy. Unfortunately, I didn't see a huge difference.

With the ECON mode off and the Engine Idle Shut Down was deactivated, I got 23.2 mpg. In comparison, with the ECON mode on and the Engine Idle Shut Down on (to get maximum fuel economy), I got 24.0 mpg...only a 3.4% mpg improvement. So a 0.8 mpg saving and with a 19.5 gallon fuel capacity (0.67 gal saving) and use of premium unleaded gas price of $2.42/gallon in Tucson, AZ, that's a savings of only $1.62 each time I fill up. Honda claims 20/27 mpg city/hwy and 23 overall, so my driving appears to be in line with their claims. From what I've read, smaller and lighter "economy" cars can benefit more from these fuel saving features so I'm not too surprised by the limited savings on my 4,140 lb SUV.

My numbers are "real life" setting from driving to and from work (no hwy) in a smaller city with minimal traffic congestion. I'm certain that different driving habits can amplify the small savings that I personally experienced. For example, living in the desert, my air conditioner was always on. I've seen reports in Edmunds.com where a 10 mpg improvement can be gained by shutting off the A/C in smaller economy cars and thus the difference in ECON is likely higher...but I'm not willing to try that here. Granted, I didn't test just the ECON feature alone so the fuel saving could have been just from the Idle-Stop feature, but it is likely a combination of the two. Bottomline, the ECON is not likely a placebo but with it's limited fuel saving, it is probably best equipped on a smaller/lighter car where the benefit may be larger...but it should not be a feature considered as a major reason to buy the car.


Hi folks I just picked up 2015 civic with this Econ button. Just to check how effective this is I used it with couple of full tanks and couple with Econ switch of and I always fueled from the same gas station. The result is this Econ does not help you at all in fuel economy I drove from home to work and back and no other use of vehicle. It gives me the same milage with Econ button on and off.

  • 1
    If you read the blurb in the extracted quote of the OP's quest in, it's no wonder it did nothing for you. It doesn't do anything beyond telling you what you can do to improve your mileage. If you don't change any driving habits, it will do nothing for you. Commented Nov 27, 2015 at 11:32

In my 2014 Civic the ECON button is most efficient when driving long distances. When driving distances longer than 30 miles I average 37-40mpg with it on versus approximately 33mpg with it off. I'm a daily driver of a minimum of 50 miles per day and definitely notice a difference with the ECON on. I agree that it does make the car a little sluggish but if you drive a lot you will definitely see the benefits of it.


When activated, ECON mode alters the Drive-by-Wire throttle system response curve in the range from about 10 percent to 60 percent of throttle pedal travel. With less gain, the throttle opening in this range increases more gradually to reduce a potentially excessive peak input for improved fuel efficiency. ECON mode also alters the operation of the cruise control system and the air conditioning system, allowing for slightly increased variances with the set speed and cabin temperature in order to further conserve fuel. http://www.netcarshow.com/honda/2016-hr-v/


Just bought a Fit and the salesman told me that itdif shut down one cylinder and make adjustments to the heating/cooling system. He advised not using the econ button in extreme hot or cold weather.

  • 3
    Do you have any documents/links that confirm what the salesman told you? Commented Feb 25, 2015 at 22:18

The Eco assist is not a placebo and it says nothing vague. It teaches you.

"is a fuel efficiency INFORMATION system designed to HELP (teach) you DEVELOP (learn) and MAINTAIN ( continue to use what you learned ) a fuel-efficient driving style. The system MONITORS (gathers data) driving style, and can DISPLAY (shows you the data on the dashboard) the impact of your driving style on the vehicle’s fuel efficiency. This feedback can help YOU make adjustments to take full advantage of the fuel efficiency potential of the Civic."

It gives you information to help teach you to develop and learn and maintain (which means to continue to drive the efficient way that you just learned) a fuel-efficient driving style . It does that by monitoring your driving style and it displays that information on the dashboard.

  • Yes, but that information is also available when you turn off the ECON via the button. The gray-to-green indicator on the instrument panel as well as the current fuel consumption are still displayed when ECON is turned off. So the ECON button doesn't have anything to do with the teaching aspect.
    – Claus
    Commented Mar 23, 2016 at 3:45

It gives you 6% less horsepower with 6% more fuel efficiency.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .