High-Pitched Motor Noise

Discussion in 'Hyundai Kona Electric' started by SeanH, Apr 29, 2019.

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  1. SeanH

    SeanH Active Member

    I have noticed a weird noise. I swear it wasn't there when I bought the car, but maybe it is more noticeable with the windows open driving next to a wall/building/car. I can hear it inside the car with the windows up if the radio is off.

    It is definitely NOT brake noise or tire noise. It is DIRECTLY correlated with whether the electric motor is engaged. I testing this by coasting along in regen1 (no noise) and tapping the accelerator (noise as soon as I press) and tapping the brake (noise as soon as I press) and holding the left paddle (again, noise on regen).
    It is either the electronics (inverter/PWM/motor/etc), or something mechanical (bearing/shaft/gear). The noise doesn't change pitch with speed, which makes me think it is PWM noise (even though the volume doesn't seem to increase with engine power). The pitch seems pretty high to be gears. Maybe a bearing. I also don't know if the motor is 'clutched' in and out, so it would be spinning even while coasting.
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  3. Some kind of audio attachment might help
  4. I am just guessing here, but if it was motor related, like a bearing I would think it would change at least some with higher speed. Hmmm.

    Sent from my moto x4 using Tapatalk
  5. SeanH

    SeanH Active Member

    I tried to record it on my phone this morning. No dice. Either it is too high pitch or too quiet. I need something like a tunnel or a parking garage (though you can't hear it over the VESS at low speeds).

    Yeah, I don't think it is mechanical. It's also not the whine I typically associate with electric motors which also changes with speed.
  6. Brennan Raposo

    Brennan Raposo Well-Known Member

    Hey Sean,
    I have had this EXACT issue for about 3 weeks and have posted it in a few topics here in this forum. It feels SO good to finally have someone who can describe it perfectly. I have tried so hard to describe the issue in both the forum and to the dealer without much luck.

    I had an appointment last Thursday for this issue. They initially told me it was VESS - I said no, I know what the VESS sound is and it's not that.
    So we drove along side a wall in the parking lot and you could hear it perfectly. The head mechanic who was driving with me at the time said this was "normal" and that the reason behind it is there is a spacer that essentially raises the brake pads ever so slightly off the rotors and that there is still some contact being made especially with humidity/rain. He mentioned that this question was brought up during the initial training that the mechanics underwent and this is how Hyundai choose to engineer this particular component of the brakes. I argued with him saying that there is NO way that that sounds is "normal" under any circumstances. I even mentioned that I get looks from pedestrians when I'm driving on quiet streets. It sound like a bearing or brake sequel from an 1980's vehicle that has been terribly maintained. He then said that it's "normal" in almost all cars and that the sound of the engine usually masks it. I told him again that this is false because I have several friends with Tesla's ranging in are from 0-6+ years old and not only do then not have any VESS, but then are DEAD silent otherwise.

    With the good weather upon us here in Canada. It's EXTREMELY audible and very annoying when the windows are down and cruising at low speeds. For me, the issue persists past about 45/50 km/h but then comes back in full force during regen or low-speed driving.

    Like you mentioned, I even attempted to suction-cup my GoPro to the side of my car pointing at the front wheels in hopes of capturing the sound. I think it's just too high-pitched for microphones to detect. The video came back with only VESS noise and no other noticeable sounds at all.

    I don't know what else to do as the dealership has written it off as "normal", but I think I'm going to write a letter to Hyundai to advise them of this.
    I also believe that it has to do with when parts begin to break in. I have about 8000 km on my vehicle to date. I think more people are going to be noticing this as they start to ramp up their mileage. Might I ask what sort of mileage you're at?
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  8. SeanH

    SeanH Active Member

    Well damn. It didn't sound like electrical noise, but I was hoping. The idea that this level of squeaking is "normal" is total BS. I'm 2 hours away from a dealer that will even touch the car, so I haven't tried that yet.
    I have about 1800 miles on the car.
    My breaks still squeak under normal use. I wonder if I can abuse them "clean" to make them less noisy?
    Brennan Raposo likes this.
  9. ajstjacques

    ajstjacques Member

    If you want to rule out the VESS noice, you can easily unplug it. It can be found in the middle of the front bumper and you can see it between the hood latch and the AC radiator from inside the engine bay. You just need to press hard on the front of the clip so it can be released and disconnected. My car is dead silent when the VESS is disconnected.

    If you want, I can post some pictures later.
  10. Brennan Raposo

    Brennan Raposo Well-Known Member

    It's funny - your thought process is identical to mine. The first thing I thought/did when I started to hear the noise was do a few high speed runs and slam on the brakes to the point where ABS would just begin to engage - very hard stops. I did this about 5 times on a dead-end street. It didn't change the sound or frequency in the slightest. The way he explained it to me was, there are these springs that are designed to hold the pads a few millimeters from the rotors. So my thought is that as these springs age, or heat up - they will relax causing the pads to make more contact with the rotors. I don't know if this is correct at all as I'm not a mechanic - but it seems that if Nissan can make the Leaf silent, Chevy can make the Bolt silent and Tesla can make all of their vehicles silent - it should be pretty straight forward.

    My concern is that if it's not a widespread enough issue or if most people don't notice/care and don't report it; Hyundai will do nothing about it. They'll have to receive several complaints before any action is taken (this is what the mechanic told me) But as petty as it may seem, I will have to drive with the windows up all summer if it doesn't get resolved - the screeching sound drives me absolutely bonkers. Sean, where are you from? Almost every dealer in Canada is trained to work on EV's. If you're not far from the boarder - that may be an option!

    Anyone have an email address for Hyundai Canada or Hyundai Corporate. I can't seem to find any email addresses for them and I really don't want to call and speak to a low-level phone agent for an hour.

  11. SeanH

    SeanH Active Member

    I'm a little surprised that there isn't a frequency vs speed component if it is rubbing on the brakes.
    I'm in Pittsburgh, PA. The cars are not sold in the state. I had to drive 2 hours to Maryland to buy the car. Because of this, the local dealerships are probably not trained on repair.
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  13. Brennan Raposo

    Brennan Raposo Well-Known Member

    That would be very helpful. I'm nearly certain it's not VESS as it deactivates after 40km/h and the high-pitched sound continues for me until about 50/55 km/h at the most. There's a bit of time where you no longer hear the VESS but can still hear the squeaking.
    But it won't hurt to absolutely confirm!

    I'm also going to find a quiet parking lot with a building that I could drive along side of and film. Would love to try to capture the sound on video once and for all.
  14. SeanH

    SeanH Active Member

    I drove back and forth past a couple of gearhead coworkers. Sound clearly audible to them. They were very skeptical about intentional brake rubbing.
    We're going to throw the car on a lift tomorrow and see if I can recreate it that way. We'll see if the car lets me spin the wheels that way and then we can try to pinpoint the location.
    electriceddy, Wildeyed and Esprit1st like this.
  15. BlueSal

    BlueSal Member

    I have this noise too.

    Has anyone tried test driving another Kona?

    On the "small issues and quirks" thread, I posted a vid of a guy who stuck a mic in the engine of an ioniq. The electric motor noise is very loud and sounds like a squeal.

    Could this noise be normal electric engine noise?
    I only started to hear it AFTER I put on new tires (rides sooo much better, cures some torque steer too.)
    Brennan Raposo and Kitsilano like this.
  16. SeanH

    SeanH Active Member

    OK. So we put the car up on a lift today and spun the tires (do not try this at home). I turned regen to zero (very important! the higher the regen, the more the wheels would accelerate and then slam to a stop). When I took my foot all the way off the brake The wheels would accelerate (creep?) to around 10mph, then regen back down. It would do this repeatedly indefinitely. The high pitched sound is clearly audible, almost like a hiss.
    We poked around all under the vehicle including the wheel wells. We're almost positive this is NOT coming from the wheels/brakes. It didn't sound like it was, plus when we spun the wheels with the car in neutral, we didn't hear the sound (which matches not hearing the sound when you let off the throttle while driving).
    We then lowered the car almost all the way to the ground and popped the hood. Again, it seemed as though the sound was coming from the center of the "engine" bay. Also, with the hood up, it sounded much more like an electric hiss than mechanical rubbing. We thought it might be coming from the inverter, but that could've been wishful thinking.
    Video is here. The VESS is audible. So is the more typical EV motor sound. But so is the high pitched noise.
    Zoomie71, robxb, EnerG and 2 others like this.
  17. Very good video, pretty loud down there, I would definitely take it to a dealer for investigation (not necessarily to the one you went before, but with this evidence they may pursue further). Service manual would be handy at this point, have you tried this?
    Note: USA may have own site
    Edit: try here-
    Last edited: May 2, 2019
  18. Brennan Raposo

    Brennan Raposo Well-Known Member

    Great Video - how hard is to to borrow that lift again? Would be awesome to have the video done with the VESS disconnected.
    That's 100% the sound I hear. the only strange part is that you mention that you don't hear it when letting off the throttle. I absolutely hear it when letting off the throttle - but again, only at lower speeds. When I'm on the highway doing 120 (km/h) and let off the throttle, I don't hear it. But when I'm on a residential street doing 30-40 and let off the throttle, I absolutely hear it.

    I wish I had access to a lift. I'd run a similar test except I'd remove the wheels and brake pads. To completely eliminate the brakes all together. It still sounds very mechanical to my ears. It sounds almost like a bearing in the motor needs some lubricating or something.

    Lastly, I'm not sure if the difference was audible in person or if it's just the video but there is a VERY distinct volume difference of the high-pitched noise when you move from the right wheel, to the left. I've watched this video about 10 times now and at the half way point, when you move over to the other wheel - the sound is about 20% + more pronounced.
  19. At first listen, all I could hear was the VESS (Virtual Engine Sound System) to alert pedestrians, but now I think you mean the sort of high-pitched sound in the background. Agree that it could very well be coming from the inverter.

    It would be interesting to hear again if you manage to turn off the VESS or get the wheel speed up enough so that it shuts off.
  20. SeanH

    SeanH Active Member

    To be clear, I agree that you can hear it over 20mph. It was just harder for me to test that.

    Yeah, I almost unplugged the VESS, but I was worried that it would throw a DTC and the dealership is two hours away :p Can anyone confirm that the car doesn't notice?
    I'll try to talk my coworkers into redoing the test with me soon.
    Domenick and Brennan Raposo like this.
  21. Brennan Raposo

    Brennan Raposo Well-Known Member

    Sounds great Sean, I look forward to it. Based on the research I’ve done, it’s pretty simple to just unplug the VESS. According to other posts you’ll simply get a “VESS malfunction” error of some sort, but that’ll clear when you plug it back in. Doesn’t sound like a trip to the dealership is necessary!

    I’m going to disable my VESS tomorrow to make absolutely certain. I’m 8 minutes from my dealership, so I’d rather assume the risk lol
  22. I did have a look at the spectrum and there is significant noise above frequencies that the VESS produces. You really should make a recording with the VESS unplugged to make any sense of this. My VESS is the upper graph recorded when the car was stationary, see image. Your VESS may be different because the car is 'moving'.

    Vess vs underside noise.png
    eastpole, Domenick and Brennan Raposo like this.
  23. Brennan Raposo

    Brennan Raposo Well-Known Member

    That’s super interesting, but as you mentioned, I think it’s a different level.
    The VESS increases in volume as the vehicle increases in speed. It shuts off at 40km/h (here in Canada at least) When driving with windows down, the high-pitched sound is still audible after the VESS shuts off. Especially if I remove my foot from the accelerator and let the regen kick in.

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