Kia ISG (Idle Stop & Go) System Explained; How It Works?


New Kia ISG (Idle Stop & Go) system offers up to 15% fuel savings!

One of the newest advances in improving fuel efficiency and reducing emissions in Kia vehicles is the engine stop-start system.

Simply put, the engine in your Kia will shut off when the car is idling, resulting in the desired efficiency and emissions improvements.

This is a particularly great feature for people who drive in larger cities or parts of the world where traffic jams and frequent traffic lights are a way of life.

This type of system is found in hybrid electric vehicles, as well as in regular vehicles that do not have a hybrid electric powertrain. Kia has had an eye on eco-friendly technologies for a while now, which is why they introduced their ISG system (Idle Stop and Go).

How exactly does Kia ISG work?

Kia’s ISG system automatically shuts off the engine when the vehicle is stuck in traffic, immediately starting it again when the driver needs to move.

Driving in the city where the traffic is heaviest means having to stop and start on a pretty consistent basis.

The addition of the Kia ISG system can cut fuel consumption and emissions by as much as 15%. A combination of different driving conditions still adds up to a fuel savings of around 6%.

The ISG system included in the new cee’d comes with a smart starter motor that is linked to an upgraded ECU. Its job is to monitor the status of the car so that it can recognize when it has come to a stop at lights, etc.

The ECU uses information from all the cars control systems to decide of the engine should be switched off.

When the car accelerates, a new smart high efficiency accelerator suppresses electric power demand, thus charging the battery when the car decelerates.

In the event that the battery drops below 75% of maximum or doesn’t have enough juice for the next start-up, the ISG system will be aborted. When the car is stopped, depressing the clutch pedal will cause the engine to restart automatically.

What that means is that by the time the driver is ready to select first gear, the engine is up and running.

The ISG system is available in a number of different Kia models.

The system was first used in the Kia Ceed model in Europe, but has now spread to other vehicles, including the Sportage and Picanto small car. The hot-selling Soul crossover and Rio sub-compact car are the US Kia models that feature the fuel-saving ISG system.

When does ISG stop working?

Kia says that the Idle Stop & Go (ISG) system does not operate in circumstances where there is risk of excessive strain of the car’s battery.

These include extremely cold weather conditions and where the engine temperature of the vehicle is not sufficient.


  1. Marvin John Perez says:

    How do you keep the idle stop and go to off? I own one and i don’t want it

  2. dfwpaul says:

    Look for the (A) button, near the instrument panel light adjuster, near the lower left side of the steering wheel. The default is ON, SO hitting this button turns OFF this feature. (ECO is similar, in that it defaults to ON, as well.)
    It does beg the question: Why did you purchase the vehicle with this option, as it is still currently a rare find?

  3. T. Shepherd says:

    I have a 2013 Sportage and the ISG works perfectly and CONSISTENTLY which is a good thing, however when I swap over to my 2014 Ceed the ISG works sporadically if at all, for exactly the same trips, (105 miles to work included).
    The dealer is a throwback to the 70’s and has wasted my time twice, they rely on telling me that the battery needs a charge and that I don’t do the ‘right sort of journeys’. Then I point out that the same journeys are ‘the right sort’ for my Sportage. This stops them in their tracks but it’s too late then because they have already had my car for two days and I am picking it up.
    A very friendly and patient KIA customer advisor says they will sort it out, but that involves going back to the same dealer and wasting more time telling the same story to five different employees. And so I let it spoil an otherwise lovely car.

  4. David Keen says:

    My ISG works erratically, but not very often. I really don’t think that the Kia dealers know what is what, as they give me conflicting information.

    The first time I enquired about it I was told that as my driving had been mainly around town I was not doing enough to charge the battery and a long run would do it – which is what the manual says.

    Then I drove 450 miles in a day and it did not work then. When I went back and said this I was told that this was because the alternator shuts down when you are travelling at motorway speeds to reduce drag on the engine and aid fuel economy.

    Come on Kia, you cannot have it both ways!

    To add insult to injury the dealer then said that his friend has a Mercedes with the same stop-go feature and it works perfectly every time.

  5. t. Pearson says:

    Have same problem with my six month old venga 2 come on Kia get it sorted

  6. Judith Drew says:

    I bought a kia rio last May (2015) it was 18 months old. Since this time the ISG does stop the engine but about 20% of the time it won’t start when i dip the clutch at traffic lights for example. I find this quite a dangerous position to be in in heavy traffic. Does anyone else have this problem? I told Wessex Garages this and it has been in twice for tests but they say it is fine. Still doing it now, no problem stopping it just doesn’t start again without me manually turning key in ignition.


  7. N.Collier says:

    I have a 2013 Ceed with the ISG system. Rarely does it work. I can do long or short runs and it appears that there is no reason that I can see that I’ve done different when it decides to work. I have reason to believe that the UK road tax is reduced because of this ISG system. If this is true I want it sorted.

  8. Jim Jefferis says:

    I have a 2012 kia venga and the isg has been working perfectly well until last week, after it was returned from a bodyshop following minor repairs to the paintwork. it has not worked since. the light now comes on when the handbrake is applied even after long journeys.
    The handbook says there a number of sensors including the bonnet and drivers door. Is it possible that the door sensor has been affected by the painting process, and is it easy to locate and clean?

  9. Martin says:

    I have just purchased a 2012 Kia Sportage. The auto stop start just comes on as deactivated when I stop. I have turned off ac and other drains but its still the same. Also the rear parking sensor constantly picks up an obstruction. Can i reset, or are they dealer jobs?
    Thanks in advance.

  10. Ann-Marie Palmer says:

    I have recently brought a 2012 Kia Ceed echo– was told the auto stop n start was the best thing. Took it back within a week, as I couldn’t get it to work, was told it won’t work if fan above 3, or air con and radio on.
    Specifically made sure I followed their guide lines, still didn’t work. Took back again, informed must be battery problem, garage told me they took battery off and charged will be fine now, but won’t kick in straight away.
    After three days it kicked in twice, then nothing for several days, then suddenly will kick in several times, then nothing for days.
    Last time it worked was about two and half weeks ago– very strange thing though, I had just started the car, had the clear window fan on full blast, and radio, only traveled a few yards to roundabout outside my house and it kicked in– so bang goes the bull story of won’t work if fan and radio on.
    Another week and half gone with nothing at all, went out for day trip, didn’t work at all going, but twice one after another when nearly back home. That was a week ago Sunday and nothing since.
    Garage promise to take back in, still waiting to be booked in, as they are obviously so very busy– two weeks on!!!

  11. Isa says:

    ISG @ KIA Cee’d it is optional or standard?

  12. Mariam says:

    Hey guys I have just bought a Kia Sportage and my amber light on the A symbol is on all the time and my car never does the eco stop thing I have only had it since yesterday and have driven a few places including work today I don’t actually know how to activate it do I have to have the aircon button on? I want to know why it’s amber and when I push it nothing happens stays amber

  13. Kakale Mishingo Malobela says:

    Well,its well understandable,that strict envision regulations,need to be adhered to in order,to have a cleaner environment,just like,when your organisation,had to bring up the stop and go system.In my country,it is of concern,since it’s still possible,to even important,a vehicle,that does Dot5 or E5,it being a car,that could have,lived towards the late nineties,and never to be allowed,to run into the country,in this time.

    As for Kia,I congratulate it,excerpt on trucks,since it’s not the only,manufacture,that is running engines,that are using in line pumps and rotary,or can we convectional engines,since if one could take,a look,into most American engines and ade,that do run,small plants,like compactors,compressors,you would find them,to be using an ems(engine management system,or electrical monitored engine operating systems.

    I hope,with cars being a global community,manufacture do need,to take a role,in sensitising countrie’s,that haven’t started,implementing environmental conversation standards to do so.This could,reduse the Wheaton,of the environment,especialy the ozone layer.

    To compliment,my statement of being concerned,about the environment as a technician,I have ideal thought of coming up,with a fuel system,that I believe if studied,it could be a solution,to a cleaner engine emissions.If interested to be of assistance,and have,a bride insight,about the idea,vist LinkedIn,and search for Mubeena’s post,and you would find me,to have published,the idea as a comment,since my device,had difficulties with publishing posts

  14. Derek Graham says:

    I agree with many of the comments above. I was told that once the battery has fallen below an 80% charge it cannot recharge to meet ISG requirements itself via the alternator. This sounds “eyewash to me as I remember dynamos being unable to recharge above a certain level and when alternators were introduced that a flat battery would be almost a thing of the past as the alternator replaced whatever charge was taken from the battery.
    Then I was told the battery was a “special” kind not the lead acid type and could only be recharged by the dealer. This necessitated the car being kept in the dealer’s garage for 2 days because after recharging the battery needed to re-establish itself via the various connections.
    Sorry Kia but if you sell a car with the claim that it has ISG and don’t publicise the fact that it will only work under very specific conditions then it doesn’t, to me, meet the specifications I was told it had when I bought the car.
    Will this situation be remedied in the future or are we all saddled with “pups”?

  15. Menios says:

    I have a kia pro ceed cvvt 1.6 2010 and has not to adding it?needs only the button or theres something else where should to change?thank you.

  16. Mark Brownbridge says:

    Like so many others, I found that my ISG would not turn on even though all the pre-requisite conditions have been met. When I pressed the button the light would not go off, so it was not engaged.

    Finally, after one month it has engaged. However, when I stop at a junction for example and ISG light goes off, so suggesting ISG is engaged I can still hear the engine ticking over. And if I press down the accelerator (without pressing the clutch) the car revs up. Does this mean the ISG is not working?

  17. Peter Pan says:

    I am sick of the ISG on my 15 plate Venga. As with other owners, it works when it feels like it. With it activatied, sometimes the engine won’t start until I de-activate it. Not impressed and will try to keep it off all the time. If it worked it would be great, but mine is C**P.

  18. keith snell says:

    i have 2012 sportage the isg worked really well when I got it, then during the winter it stopped I assumed this was because of the cold weather and the engine temp. Now it is getting warmer and isg still does not on investigation I realised the thermostat was stuck open so the engine temp was till in range for the engine so no fault indicated but the required bottom tem temp for isg was never reached. Change thermostat still the same isg not working, Any one have ideas?

  19. peter pan says:

    Just been told by Kia Dealer, that battery needs changing every 2 years due to ISG. Mine was 1 month outside the 2 year warranty and I was quoted £240 for a Kia replacement. They are having a laugh !
    Surely Kia should have sorted the ISG problem by now. This is not funny.

  20. Goodie 2 shoes says:

    Seems that i am not alone in finding that the ISG is not very good mine only work for 3 weeks but now not a thing out of it, you pay the extra for this equipment and its cr=p will be back to dealer to see if its covered on the warranty. Ive got my doubts//////

  21. Mandy says:

    My 15 plate Kia pro c’eed is rubbish! I got it in October last year and loved the start stop that worked for the first three weeks of owning the car (was given a brand new battery as, now I have discovered it has an electrical fault which sees my interior light come on sporadically). It get stuck in fifth gear if ever I stop in it which has caused me a couple of near misses. The start stop won’t even turn on any more. I put it down to the winter cold weather as previously suggested on forums but this has made no impact!

  22. Kathryn Cox-Hockey says:

    My ISG stopped working within 2-3 months of buying my car. I find this infuriating and have been told it is because I don’t do enough long distance driving so my battery doesn’t hold a high enough charge to make it work. If this was true, surely my friends car would have the same issue. (She’s a driving instructor) Any suggestions? I would like this fixed but m fed up with being palmed off

  23. jess says:

    I’ve had two Kia Cede eco dynamic’s now and the first was a 59 plate it was great, the eco stop worked every time. Next is the current one a 64 plate eco stop worked every time until the winter so thought ok it’s cold. Had a service this Spring and warmer temperatures guess what it’s a no go. Gone back to the dealership and was told that you have to do 28 MILES!? It worked before just after 5 wish. Then went on holiday to mid Wales from Cheshire, NO ECO STOP NO MOTORWAYS. It’s been in now three times checked everything and now at this present time is having an new battery but they have said there is no guarantee that this will work, so I told them I will run it about a but and if it doesn’t work it will come straight back immediately. This action prompted a response of 50% off their battery! So we’ll see what happens.

  24. David James says:

    “How it Works?” In the case of my Ceed, it doesn’t. Not once in the year I’ve had the car. My dealer told me it was classed as a “luxury item” as if that meant it didn’t have to be functional. Kia should be ashamed.

  25. Stew says:

    just purchased a Kia Seed 1600 diesel on a 65 plate, also having problem
    with ISG working spasmodically. From what I’m reading about it I feel quite miffed that this looks like what I have to accept, I think pressure should be put on Kia to get this problem sorted out, there are obviously a lot of pee’d of drivers out there.

  26. Mitchell says:

    My Optima isg Symbol comes on the dash as amber, and the engine never switches off, I’ve tried everything but can only assume it’s a fault? Can anyone help?

  27. Gary Cocking says:

    I purchased my 16 plate Carens 3 with ISG just over 2 weeks ago and the auto stop has yet to work. Shame as had auto stop on a Renault Scenic which worked all the time. Might have to visit the dealers.

  28. This is really helpful information – My 2017 Sportage is intermittently using the ISG system. Seeing as it is sub 10 degrees I guess the system won’t work due to battery strain.
    Great info – many thanks!

  29. Jeff Burrell says:

    Same problem as mentioned many times above. The ISG on my 66 plate Kia Ceed has only worked once, when I did a round trip of 100 miles. On normal day to day driving it just won’t work. It’s a bit strange that other manufacturers seem to have success with their vehicles but Kia just come up with excuses.

  30. Gary says:

    I have a 2017 automatic sportage. The ISG appears to work as designed while in drive with the brake firmly applied, but I can’t understand why the engine restarts when you shift to Park. Totally illogical! Is there a setting I’m missing?

  31. Mr Kevin Malone says:

    I have a 2013 Kia Ceed, I bought it about 2 years ago. As soon as I bought it the ISG, (stop start) didn’t work at all, it worked only about 2 or 3 times during that 2 years. I could not figure out why it didn’t work. I went on-line to find if anyone had the answer, all I found was everyone seemed to have the same problem. I also got the same reply as everyone else from my local Kia while getting my car serviced that the ISG system is not the best, the need for long journey’s, new battery, perfect conditions etc etc. During the winter of 2016 I felt it was time for a new battery, I had it fitted by Halfords, but I was disappointed, the ISG still didn’t work afterwards, While on-line I learnt a lot about the Kia ISG system. I learnt that it was a very ‘Smart’ system. To repeat what I read: ‘’Start/stop is active when a surplus of power has been build up. Building up (or earning) a surplus of power is achieved during deacceleration. During deacceleration no fuel is being supplied to the engine (fuel cut) which means that the weight of the car is turning the engine around and hence also the generator and thereby charging the battery with extra, CO2 neutral power, (free power (or charge of battery) that is not needed for running of such things as air con, heater, lights, entertainment system, car electrics etc).
    When deaccelerating it is important that the car is kept in gear and the foot is off the clutch pedal. ‘’ In other-words as you are driving, when it is safe to do so, (no traffic behind you), intermittedly, or when-ever you can, take your foot off the accelerator pedal, (do not coast, you must be in gear), do the same when approaching traffic lights, junctions round-a-bouts traffic cues etc, in other words refrain from approaching traffic lights, junctions etc at 100 mph & then slamming on the brakes, this type of driving style does not charge the ISG system. After realizing this, my 2013 Kia Ceed ISG system now works perfect every journey every day, even with air con on setting 2 or 3 entertainment system & lights all on, (mine has daylight running lights on). When the ISG switches the engine off at traffic lights etc, it is awesome. A brilliant system.

  32. john mathew says:

    i bought a sportage 16 reg. two weeks ago. the ISG light turn on/off at times. is this system includes the 7 year warranty?

  33. Deborah Morriss says:

    How interesting, was thinking it was just my c..p ‘15’ plate Venga not working properly. Interesting because my husbands Sportage works fine and he uses his car less than mine!
    Kia garage seems dis interested. Funny that when they are selling the product, different story and Kia can do no wrong… as you are all saying, car is not offering a function that it is advertised with, so what’s khappening??? Last service. Told the same thing. Low battery. System doesn’t kick in. Charged up battery, told it may or may not work, it didn’t!!! Sorry did I pay for an eco/green/ function????
    Perhaps we should contact Watchdog or other consumer programme to get taken seriously.

  34. Carlene says:

    I have a 65 plate ceed 1.6, brand new from show room 4miles on clock, and although im quiet heavy footed while driving my stop and start worked perfectly fine… for the first year and bit, now i think my car has amnesia and dont even know what it means anymore.

  35. John says:

    The ISG on my 2016 Ceed SW 4Tech (gadgets galore) worked originally but not for a long time. I have had the full list of excuses from my local dealer, but they eventually admitted that they have never got a failing car to work.

    As an electronics engineer with a fair knowledge of batteries I query the confusing excuses around this component. Does the control system have a battery charge-discharge meter (as used to keep track of your laptop battery)? If so there ought to be a software solution.

    Is there anyone at Kia prepared to come clean on the issue?

  36. Derek Wild says:

    Given every excuse why the ISG doesn’t work from:-
    1. Having your lights on but the cube light are o/k because they don’t put a strain on the battery.
    2. You have the heater blower on above the minimum setting.
    3. Temperature outside is too cold. (Laughed at that one as we were in the middle of a heat wave in 2018).
    4. Not doing enough miles ( happy about that one) but what about when the car does several hundred miles 4 or 5 times in a week. Sure the battery should be fully charged by then!!
    5. The battery could be faulty but they have confirm that the battery is ok, just a bit flat. Oh and by the way, you need a special charger to charge it up

    My vehicle has been in 4 times in the last 2 years with the same fault(?) and every time, I have been given a car for 3 days whilst the battery is charged up. It then works once or twice and fails again.

    A total waste of mine and their time and being fobbed off each time that the problem is my doing.

    Spoken to Kia customer service about being this who state that all their dealership are fully trained and whilst they are sorry to hear about this, they suggested I talk to another dealership. Great when you have a long term service agreement in place.

    Very disappointed in Kia.

    Next week, I will be getting the battery state checked and then I will be going on my holidays where I will be doing lots of miles and then I will be back to the dealership to have it checked again.

    If the battery state still remains a problem then either the charging system or software is at fault or perhaps it true that once the battery state drops below a certain value, I will need the dealership to top it up. Best be driving round with no aircon on, zero lights and hope the climate change results in a lot warmer winters.

    Come on Kia, sort it out!!

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