Resetting ECU Settings On Hyosung


First of all, you must understand what is ECU in general on both motorcycles and cars are for and think about it again if you really need to do this on your bike? The Engine Control Unit (ECU) learns” about your engine as you ride or drive your machine. The “learning” is actually a process that the ECU uses to track the tolerance changes of the sensors and actuators on the engine.

*This is just a sample picture of ECU that I found online.

However, Hyosung’s stock ECU neither stores codes after the ignition key is turned off nor does it have a memory for storing any mythical learning.

It has a pre-programed set of parameters and based on the sensor inputs adjusts the fuel injector opening times accordingly. It will NOT learn anything but the base map settings can be reset if it’s necessary.

Myth & Reality?

The Myth

There is quite a bit of mythology revolving around resetting the ECU. Many people mistakenly believe that they need to reset the ECU after installing major engine modifications or parts such as exhaust pipe. Others believe resetting will resolve engine problems. Neither are correct. (Yes, resetting ECU may help in solving engine/electronic problems but the diagnosed errors has to be fixed first)

The Reality

The ECU is always tracking the engine’s sensors and actuators when the ignition is switched ON. Resetting the ECU does not cause the ECU to learn engine changes any faster. The ECU is always  tracking the gradual changes in the engine sensors and actuators. The ECU never gets satisfied with a setting, and is always updating the trim values. It will discover whatever change you made to your engine and make the appropriate changes when you’re riding.

There are only two reasons why you would want to reset your ECU. One is to clear a CHECK ENGINE error code after fixing the problem that caused the error.

The other is to reset the spark advance trim value. The advance trim controls how much the timing is retarded from what the factory engineers considered optimum. I’m not sure if this applies to a Hyosung machine but it was shared over a coffee session from my friend.


I reset the ECU, and now the bike runs rough! Why? The engine may run rough or idle poorly right after ECU reset. The ECU now has default numbers in its base settings – it has to adjust them to match the tune of your engine and its sensors and actuators. You will need to ride your machine for quite sometime before the engine will settle down again.

How To Reset?

If you want to reset the ECU settings on your Hyosung/Blade/Comet for whatever reason you think it’s good, please see the steps below:

Disclaimer:  Do it at your own risk. I am not responsible for any damage caused by this action.

1. Turn OFF the engine, and unplugged the ECU from your bike. (Also ensure to turn “OFF” the ignition switch, or electronic parts may get damaged).

2. Remove the -ve and +ve wires from the battery terminal respectively and leave it for 10-15  minutes (some says only -ve would do ) Well, you decide?

Note: I can’t stress enough, removing any battery terminal of a running engine is strictly prohibited. The moment such removal is made, damaging counter electromotive force will be applied to the ECU which may result in serious damage. On another note, never connect an ohmmeter to the ECU with its coupler connected. If attempted, damage to ECU or sensors may result.

3. Plug the ECU back to your bike,  reconnect the wires to the battery terminal. It is also advisable to measure voltage using a voltmeter at each terminal. check to make sure that battery voltage is 11 V or higher. Terminal voltage check at low battery voltage will lead to erroneous diagnosis.

Note: Battery connection in reverse polarity is strictly prohibited. Such a wrong connection will damage the components of the FI system instantly when reverse power is applied.

4. Turn ON your engine  and leave it running idle for 15 minutes (Do not rev the throttle)

3. Once you’re done with the 15 minutes idle running, turn OFF the engine and leave it for another 10 minutes.

4.Finally, turn back the engine ON,  ride your bike in a traffic for a day or two (If you plan to ride in traffic often) or Rev your bike on a highway in high RPM whenever you switch gears (If you plan to ride on long distance often)  and eventually your bike will accustomed to the way you ride.


In my personal opinion, I’ll never reset the ECU settings unless I have issues with the engine. i.e. There is an error(s) code detected etc.

i.e. I been riding my bike below 100KM/h when I initially got my bike and when I rev it at higher RPM to go faster (150KM/H), it seems to be struggling. However, when I rider it for a about 1 hour, it seems to be fine. This is because the ECU has relearned / accustomed to my riding style without even resetting the ECU settings. So do you think still that you want to reset your ECU settings? think again 🙂

If you have any questions, drop them at the comment box below and feel free to share this article via the social buttons.

54 Responses

  1. David says:

    Hi Bharat,

    The fix is very easy (only takes 15 minutes or so) and cost is not high. Purchase this:

    I bought this module out of desperation and did not expect much improvement if any at all. Surprise, surprise! Not only did it completely (100 %) eliminate the “dead zone” between 5000 – 7000 rpm it has improved throttle response at all ranges and seems to have increased both torque and horsepower. Really have no way of checking if there has been an increse in torque and horsepower but the dreaded “dead zone” has completely vanished.

    Hope this helps.

  2. Bharat Naik says:

    My gt650r goes fine but when i leave the throttle and when it comes bellow 3000 then it goes to off throttle and when it reaches to 2000 rpm it goes to on throttle

    • Rider Chris says:

      Hi Bharat, See David’s comment above

      • Bharat Naik says:

        Sir now I’m getting one more issue with my hyosung gt 650 2012 like when i start and if pull the throttle if goes off have to wait for about 3-5min until the bar goes to 2-3 and the bar never goes above 3 bars even when really hot

      • Rider Chris says:

        Looks like you have multiple issues with your bike. I would suggest that you bring it over to a dearler and get them to check further using diagnostic tools.

  3. Wilma says:

    Thank you for the article, very detailed.
    I was wondering if a reset of the ECU would work for my GV250 2009 model.
    In January, on a hot day (37C) in very bad stationary traffic, my bike stopped after about 40 minutes of very slow, intermittent movement. I waited for 30 mins, then I could start again.
    I could not start the motor straight away. The starter motor would go, but no fuel would come through.
    Since that incident, my fuel supply stops after about 8 km of driving. Because the bike is still moving, I can roll to a safe place (I dont even have to switch to neutral), have to wait for 10 to 15 mins, then the bike starts again.
    The mechanic had a look. he can replicate the issue, but says he cannot find anything mechanically wrong with the bike.
    Due to the fact that the fuel supply instantly stops while driving, without sputtering to find more fuel (eg when you need to get fuel), we think it is something electrical.
    Could it be the ECU learning at the initial incident to stop when the engine gets too hot?
    Looking forward to your insight, about to give up the bike, which I dont really want to.

  4. Ala Atmeh says:

    After appreciation.. I have read the subject it is very good .. but I have a problem with my new aquila 250 efi. I have new motorcycle zero KM it`s performance is good on high way but in the city it is not good it seems cutoff and run again so yo can`t drive at the first or second gear smoothly in city .WHAT can I do ????

    • Hi, If I understand this correctly, you mean that your bike will have problems if you ride slow? What exactly will happen? does it jerks on low RPM? i.e. below 4000RPM?

      • Ala Atmeh says:

        Thanks for reply … exactly it is jerks on low RPM.
        that is the best Description , mechanically perhaps one cylinder ruining and the other one is off for moment..
        thanks a lot

      • In this case, your plug cap(s) are broken. There is 2 plug caps for Hyosung, you can either tape it with electrical tape and see if it resolves the issue or replace them.

      • Ala Atmeh says:

        hi every body . i check the plugs it was new but I do some thing else and make difference , my exhaust was drilled to be louder . I Return it as the original and making reset to ECU really there is a big difference .Thanks a lot

      • That is a great news! Cheers

  5. Hi Darren, if you’re just adding on Slip On muffler, you don’t need to flash the ECU.

  6. Darren Williams says:

    Hi Chris do I need to flash the ECU if I add a a slip on and an air filter

  7. Tomas Roman says:

    Hi Chris
    I have a 1993 1400 vs Intruder that kept stalling on me every so often. I took it to a shop they diagnosed that I had to change the coils. that being said I ordered new new coils and the problem did not go away. the carburetors were checked, spark plugs removed and replaced with new and still the problem remains. The mechanic has been doing work on the bike now for two and a half months attempting to find out why the bike stalls sometimes and does not other times. The last thing he says he wants to try is replacing the ECU. it seems to be the only thing left to change since all the switches including the brake switch turn signals Etc. I’m a bit frustrated since I haven’t been able to ride the bike now for two and a half months and I’m about to order an ECU. Just need some advice at this point. I’m sort of at the end of my rope a new ECU cost upwards of $900. I thank you in advance for any advice you can offer. Thanks

    • HI Tomas, sorry to hear that and it looks like the technician may have already tried all the possible things to diagnose the problems with your bike. I would suggest that you borrow someone Else’s ECU and try on your bike first and see if that resolves the issue? You don’t want to spend $900 for something which doesn’t solve the issue you’re having. If you can’t find anyone to borrow the ECU, try to ask in a VS Intruders’ Facebook group here – (You will need to have a facebook account before you can see those Intruders group). You can share the issues you’re having there as well and see if there is anyone else is having the same problems. Cheers.

      • Tomas Roman says:

        Thanks for getting back to me I tried and I’m trying an alternate ECU to see if that fixes the problem. Otherwise it’s just going to be a mystery. Thanks again
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  8. David Holley says:

    Hi Chris:

    Bike is a 2012 GT250 (completely stock) with 2000 miles. When engine is turning less than 6000 rpm and I go from on throttle to off throtle and back to on throttle (as is sometimes required in slow moving traffic) the bike lurches (very hard). In slow traffic I must constantly use the clutch to counteract the lurching. Bike starts well, idles smoothly, and otherwise runs flawlessly and is a pleasure to ride. The low speed / rpm lurching is difficult to live with and there are no Hyo dealers nearby for support. Any thoughts would be greatly appreciated.

  9. Sufy Zahary says:

    Hi Chris..I ride naza blade gt250r 2013.. i have a problem with when revving up the bike.. i feel like the revving is a bit lag, its like the RPM a bit late to go up when i pull the throttle.. i’ve already clean the throttle body with TB cleaner, check the throttle cable but its still the same.. so my Q is.. is it because of the mapping of the ECU?? or because of the TPS?? or is there other problem?? what should I do.. TQ CHRIS

  10. Steven Devereaux says:

    Hi there Chris, I have a 2012 Hyosung gt250r.
    It has a screaming demon pipe attached to it, my problem is it feels like it is running rich, i can smell a little bit of fuel, but not alot.
    it stutters and backfires a bit at low RPM/idle (idles sounds a little rough,hops between 1650ish-1500 sounds like its wanting more air) but when i wind it out (above 5000) its not so bad.
    Even at the lights, unless i rev it to clear out what feels like unburnt fuel before i can take off otherwise i can stall.
    Any chance a reset but solve this problem, it dosnt feel like a major issue, its more a pain than anything else.
    feels like a back compression issue?

  11. Pramod Nair says:

    Hi Chris, Need Help.
    After riding my GT650R for say 20km or so and when i stop my bike at the lights or toll or some place, the idle rpm drops to 1000 & below and the engine switches off. Then to turn on, i have to turnoff the key and again turn on the engine. and then the bike works good for say again similar distance.
    My bike is more than 3 years old. This problem i am facing since last 2 years. I took it to service center and they checked. but according to them there is no problem as and when they take for test ride they dont face any problem. Also, i took them once as pillion in heavy traffic and on highways but the problem did not come up.
    Can you please guide me what would be the problem??

    • hi, have you changed your spark plug? did the service center check on your fuel pump? Also, before you ride, what is the RPM Idle? The standard idle should be between 1400 and 1600 rpm.

      • Pramod Nair says:

        Thanks for your reply. I haven’t changed the plugs yet. My bike idles @ little less than 1500 rpm. Also, when the service center guy checked, he did not face any problem. My bike rides good initially for say 20 km or so but when i come to a halt, the idle rpm is at 1000 and slowly it turns off.
        When i start the bike, it again idles @ little less than 1500 rpm for similar 20 km and again the same story. cant make out what would be the problem. 🙁

      • Try to increase the idle time to 1700 (It should no be lower than that) and change the spark plugs and see how you get on.

      • Pramod Nair says:

        Thanks Chris. Will try. But, how to increase the idle rpm on fuel injected bikes? If you can assist with any video link or a brief description, that would be of great help.
        Thanks once again.

      • Hi, Unfortunately, you can only mapped back the RPM via the Diagnostic tool. You will need to go to Hyosung mechanic.

      • Sivakumar Viswanathan says:

        HI Pramod, i also have the same problem. Looks like there are many with similar issues. were you able to fix yours ?

  12. David says:

    Hi Chris! My GTR 650 only show CHE. Can I reset the ECU?

  13. Pablo Cordero says:

    Hi Chris,
    First of all, thanks for sharing this post. I have an Aquila GV250 EFI. it has FI lamp off now. when i do the self test the check lamp blinks errors ” “stored” on the ECU anyway. Do you think that i should reset the ECU?

  14. Pablo Cordero says:

    Hi Chris,
    First of all, thanks for sharing this post. I have an Aquila GV250 EFI. it has FI lamp off now. when i do the self test the check lamp blinks errors ” “stored” on the ECU anyway. Do you think that i should reset the ECU?

    • Hi, Pablo, You might want to check the electronic fuses at the rear seat and ensure they are all OK and intact. Also, check the connectors on the ECU and ensure they’re intact as well. If you’re still having problems, you can try to reset the ECU and see how you get on. Cheers and Happy New Year.

      • Pablo Cordero says:

        Hi again, Chris. I just wanted to let you know, that the codes went off, so I didn’t have to reset the ECU. I want to ask tou about another problem i have, is about oil level. Sometimes after a long journey, 500 km or more, It went under the LOW mark on the window inspection. Do you think is burning oil? I used Motul full synthetic 10w40.

      • Hi Pablo, I hope you are using the authentic Motul oil. I had the same problem like yours if I do long ride on Repsol but when I changed to Liqui Molly 10W50 fully synthetic, it works for me, i.e. no more burning oil. Perhaps you can try 10W50 Motul and see how you get on.

      • ATHEPISTA CO says:

        yes, don’t use motul, before i have experience using 10w40 motul 5100 oil getting less make me so scare ,althrough it not so many mile, just less mile i riding. i use liqui moly 10w40 street , xrev 4t , castrol power 1 4t no problem , smooth as butterly. semi , semi then fully syn repeat safe enough.

  15. Mohamad Aluai says:

    hi good day and berry good morning to all my blade is 2014,injection model.i just got problem on my bike. when
    engiene is hot at the congested area the idle timing disturb.i change the coolant rediator more big than existing already,but still same problem.I don’t have any idea can you give you idea how I can solve it .

  16. abd razak bin md jani says:

    hi morning!my blade is 2014,injection model.i just got problem on my bike. when engiene is hot the idle timing disturb.i change the cap plug already,but still same problem.can you give you idea how?

    • Hi Sorry for the delay, I would suggest that you check with a local foreman. If you’re in Klang valley go to NAZA SC, Bard Paya Jeras or Gewes in Pandan Indah.

  17. jonathan says:

    hi, I have some doubt about the fuel injection.. if I want to condemn the headlight of my motorcycle.. is there any changes will happen or any abnormalities may occur? what is the most safest way to condemn the lights? many thanks

  18. Sam says:

    Hi Chris,
    a month ago I lost power on my ST7, when testing the rectifier/regulator it was giving out 6 to 7 volts, I changed it and now it is testing 14V. The FI indicator is still showing on the dashboard and would not go away after restart, checked for faults recorded and it displays:
    0562 Battery Voltage Low
    0122 TPS Circuit Low Voltage
    0850 GP or Clutch Lever switch malfunction,

    Do I need to reset the ECU or to disconnect the ECU.

    • Chris (Hyosung Rider) says:

      Hi Sam, as part of the troubleshooting, you can first disconnect the ECU, then ensure it is properly fits in, try for a day and see. Failing that, reset the ECU. Please do this when your motorcycle ignition is SWITCHED OFF. Cheers

  19. Chill says:

    Bit miss leading, with regards to the ECU you have pictured it does store the error codes from the 2012 models and onwards.

    • Chris (Administrator) says:

      Hi Chill, The ECU neither stores codes after the ignition key is turned off nor does it have a memory for storing any mythical learning.

  20. sunny says:


  21. Hylife says:

    Utter nonsense.
    The Hyo ECU neither stores codes after the ighnition key is turned off nor does it have a memory for storing any mythical learning.
    It has a preprogramed set of parameters and based on the sensor inputs adjusts the fuel injector opening times accordingly. It will NOT learn anything and cannot be reset.

    • Chris (Administrator) says:

      Hi Hylife, Thanks for sharing your thoughts, I had a chat with other experienced rider and technicians, some of them agreed with you. Cheers

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