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Honda Accord Hybrid Harmonic Drone/Noise Suppression

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  • walzowalzo Posts: 3
    my car hits what i can only call a harmonic droning vibration at around 17500 rpm and also at 8000 rpm. Does anyone know what causes this... the dealer does not.
  • c1teach22c1teach22 Posts: 1
    I have about 5500 miles on my Honda Hybrid Accord and I am also get a harmonic droning vibration. I haven't taken it to the dealer yet but this must be a common problem.
  • bwspoonbwspoon Posts: 2
    I am having the same problem. I have 3400 miles and it started about 1000 miles ago.

    It happens at all speeds. I took it in to the dealer last week and it did not make the sound. I was frustrated when the mechanic scratched his head. This is a LOUD noise and I believe it is affecting my mileage. My gas mileage is about 20 mpg around town and 24.5 on the hwy.

    It is unpredictable and happens in D and D3. It stops when I accelerate.

    Today filled up before I made a 80-mile HWY trip and tripped the mile meter. No noise and my mileage was at 32.5 MPG. It started making the noise after about 60 miles the noise started and after 80 miles my average mileage is down to around 27 MPG.

    Anybody else have low mileage? What are you getting?

    Love the car and I want to be proud, but am embarrassed about the mileage and the noise.

    It is helpful to me to see that other owners are having the same problem and encourage other readers to boost the knowledge base. I took it back to the dealer today and it made the noise with the service manager in the car. I have an appointment next Monday and will try to remember to share the results on this forum.

  • Karen_SKaren_S Posts: 5,095
    Check Honda Accord Hybrid Owners: MPG-Real World Numbers to see what other owners are getting for MPG.

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  • bwspoonbwspoon Posts: 2
    Okay, here is the skinny on the "harmonic drone". Evidently, as my Honda dealer tells me, I am "one of a couple" of owners (nationwide) that has a Hybrid Accord with problems with the "Anti-noise Generator". If you are going down the road when the noise starts and you open the front door and it stops, then you may be having problems with your white noise generator. The fix is to order a new set of front speakers. I am serious. If it weren’t my car I would think it was funny. I mean there is some really good comedic material here. I am going to suggest to my 16-year-old son that he rename his band "The Harmonic Drones"

    Anybody else, or am I really "one of a couple"?
  • My new Accord Hybrid also has the drone problem. At 55 Mph with four passengers the car goes into a very loud harmonic drone. I took it to the dealer today and they were unable to diagnose the problem. I suggested that it might be the noise cancelation system and they thought I was crazy. Now that I have your experience to point to maybe they will listen. Thanks for posting.
  • I get this too. I seriously doubt that we are "one of a couple" of people nationwide with this problem. It occurs on longer trips, especially when going downhill. In my case, it only tends to occur when the green lights are re-charging the battery, and simply shifting down to D3 or pushing on the accelerator will eliminate it temporarily. How annoying! It started doing it at around 5K miles. I worry that the mechanic won't be able to hear it or that they won't believe me, but seeing the other posts here makes me glad I'm not alone. I'm taking it in to the dealer this week and will let you know what they say. Good think I got that bumper-to-bumper warranty thing.


  • demianmacdemianmac Posts: 1
    I just got my accord hybrid back from my honda dealer. I told them a heavy bass vibration would happen at 1.5 RPM. They told me it was an interference with my 12v connection.? I am thankful I read this forum. It really looks like a lot of people are having this problem. I think Honda needs to get with it. I am tired of the "Harmonic Drones".

  • My Accord Hybrid is in the shop with the harmonic drone problem. I have contacted Honda Customer care and they do not have a service bulletin on this problem and did not have a fix they could recommend. My dealer has ordered new speakers, but they have no idea if this will fix the problem. Have you had yours fixed yet (new speakers)? Is there any word from Honda on this problem? I have verified for myself that it is the noise cancellation system. When I put my finger over the front Microphone the sound gets even louder. If I open the door the sound goes away.
    Thanks for any information.
  • The dealer just called and said they replaced the front speakers and the harmonic drone problem is fixed! I will believe it when I drive it.
  • midnightcowboymidnightcowboy Posts: 1,978

    The problem you describe is a ANC design issue. Replacing the speakers can only temporarily circument the problem; it will reoccur! When the VCM shuts down 3 cylinders it generates noise and the threshold level in the ANC system does not sufficiently attentuate the frequency spectrum, because instead of shifting the phase 180 degrees and apply the phase shift frequency to cancel noise the phase shift does not take place exactly because the speakers/microphone cannot correct reproduce the sound and instead you encounter a noise feedback loop which amplifies the part if the noise rather than cancelling it.
  • That is what I was afraid of. Since the microphone is not exactly where your ears are and the speakers are not exactly where the noise is generated how can the noise cancellation system work for all conditions? It seems to me that there would be nodes of positive interference throughout the car! The question is why does it work after the speakers have been replaced and is there a better long term fix? Can Honda reprogram the ANC? What I noticed is that the problem would change depending on the acoustics of the car. I.E. how many people and how much luggage etc. I have the car back with new speakers and the noise is gone for now.
  • s2khahs2khah Posts: 26
    I am buying an HAH and got more information from my Honda service manager. The ANC system just addresses the exhaust resonance generated by switching to 3 cylinders since the exhaust is tuned for 6 cylinder operation.

    It has a very defined frequency band pass that generates the noise cancelling output from the speakers. This resonance frequency likely occurs at several locations in the RPM spectrum although he could not say where. But likely this makes it quite insensitive to generating output caused by random noise in the car.

    There are 2 microphones for this system in the passenger compartment. One visible on the center front head liner and another low the drivers side area of the rear window.

    I figure that noise cancelling headphones have a good history, so Honda likely uses the best tech to do this. The cancelling uses the radio amp to run the speakers so it very well might still allow those frequencies through that are in normal output from the radio/stereo signals.
  • I am having what I think to be a harmonic noise issue but is different than what I believe several people have reported. I park my HAH in a garage at home and at work so it rarely sits in the sun. But, I have noticed that only recently (past 10000 miles) if the car is out in the sun while I am out shopping or I have a long drive home that it begins to whine with a strange harmonic noise. It is difficult to describe, but it is not the low bass-like frequency some have reported. It sounds more like a whine that sometimes starts low but then becomes high pitched sounding kind of like a whale call (seriously!). This happens when I am auto-stopped, creeping along in traffic, and at highway speeds. It has happened with the A/C on and off, the brakes on and off, with the radio on and off, and with the windows up and down.

    I took my car into the vendor referring to the comments on this thread regarding the ANC. The vendor called a "senior tech at corporate" to talke about the ANC problem. It is specifically to address the low rumbling harmonic and they are working with the ANC vendor and do not yet have a solution. Anyone who has had their speakers replaced have not had the problem fixed permanently.

    Does anyone else who has the harmonic problem have the type of noise I described? I am at a loss and since the vendor can't find anything wrong (no surprise there) I am constantly worried it might be a safety issue.
  • s2khahs2khah Posts: 26
    By description this almost sounds like something that is similar to alternator "whine". Alternator noise was a problem on earlier cars that had insufficient electrical noise filtering and resulted in a whine like noise that came through the speakers when the radio was on.
    See if the noise is related to the engine speed (look at the RPM gauge) or whether the eco batteries are being charged or discharged. It gets higher in frequency with higher RPM.
    Since the radio amp is on whenever the car is on (due to the ANC system) this may still be coming from the speakers even if the radio is off.
    I think opening the drivers door shuts off the ANC. Don't do this while driving! See if the noise stops.
    If so, it may be a problem electrical filter (or supressor) in the wiring. With age maybe a loose connection etc. Talk to Honda.
  • Cool -- now I finally know what that noise is called. I too experienced the "drone" and, of course, was believed to be insane by my service manager (not to mention that because I am a woman I was given even less credit). I actually made the service technician ride with me so I could prove the noise was happening and true to form, the car performed. Thanks for the info on this most annoying occurrence.

    Clearly, there are more than "one or two" Accord Hybrid owners in the nation who have experienced (or are experiencing) this issue.
  • s2khahs2khah Posts: 26
    Sorry if I misled you. But I was just describing what the cause of the sound might be, and not that I have ever experienced it (especially with my Hondas).
    We have had no noise problems, or others for that matter, with my wife's 05 HAH, my daughter's 98 Civic, my other daughter's 03 Civic and my own 01 S2000 (only noises are the exhaust notes at 9000 rpm).
    We have had excellent service from our Hondas and I hope yours is healthy soon too.
    Good Luck.
  • So how many owners are or aren't having this harmonic problem? This is the first thing that has caused me to re-consider buying an 05 HAH. I usually don't like to buy first year models and I believe I'm correct in thinking that the 05 HAH is the first year to employ the 3 off 6 on engine. I'm really wondering about the durability of this engine... is it the same 3 cylinders that always go off- what about uneven engine wear? And most importantly, why does Midnight Cowboy think that the problem will just come back again and again?

    When I test drove the car I was impressed at how quiet it was especially at red lights. I don't want to buy a 30k car and have to crank up the radio to tune out some irratating noise.
  • s2khahs2khah Posts: 26
    Couple of comments for Honda's 6 to 3 operation.
    1. The HAH is not the only Honda with 6 to 3 operation. I believe the Odessy has it and perhaps other models but not sure. (A friend just returned from an 1800 mile vacation with his 6 to 3 Odessy.)
    2. Many Honda engines have been equipped with V-Tec variable valve technology (upon which the 6 to 3 operation is largely based). V-Tec has been around much longer than my own 2001 S2000 has it and it is a very proven and very reliable system.
    3. Honda and indeed those of many other Japanese marques, seem to produce cars which the are extensively tested before offered to the public. (My experience with owning first run (3) 240Z'z and (2) Diesel Maximas were justification for me as I put 50k+ miles per year on the cars).
    I suspect that there have been many 6 to 3 Hondas sold this year and if the few complaints that have appeared in this forum are any indication, complaints may be rare.
  • cal_calcal_cal Posts: 39
    I have been driving my HAH for 3 months and no harmonic noise, drones, no nothing. It's been a really good car.
  • ecogeekecogeek Posts: 1
    Glad to read that others were having this problem. I called my Dealer and asked them if they had heard of the ANC issue and he told me there is a recall out for the ANC. So all you have to do is take your HAH in and a couple of hours later it's fixed!

    I'll post in here when it's done and let you all know how it goes. :)
  • If your harmonic drone sound is most apparent between 1500 and 1700 RPM try this.
    1. Accord Hybrids with Navigations system: Turn the ignition switch to ACC (1) or ON (II)
    2. Turn the Audio Unit off. (Radio on and Off button, push to off)
    3. While holding down the upper part of both the "CH/DISK" and "SEEK/SKIP" buttons simultaneously, press the VOL/Pwr knob.
    This will place it in Diagnostic mode...DIAG will appear in the upper window above the Nav unit.
    Now while the engine is stopped and while in DIAG mode, turn the ANC ON and OFF by pressing the SCAN Button, you may have to push SCAN button ON and Off a couple times... While in the OFF mode, This will be displayed in the upper window above the Nav unit..... a low frequency hum (50HZ should be heard. While this low frequency tone is sounding turn the engine on and the sound should go away. IF it does your ANC is working and now is reset to the on position automatically. Now drive your car and see if the low frequency drone is gone!

    If you do not have the NAV unit follow this procedure.
    1. Turn the ignition switch to ACC (1) or ON (11)
    2. Turn the audio unit ON.
    3. While holding down both the "Preset1" and "Preset6" buttons simultaneously, press the AUDIO PWR knob.
    4. "DIAG" will appear on the audio unit display to indicate you have entered the self-diagnostic mode.

    NOW, while in Diag mode turn the ANC ON to OFF by pressing the #1 button, A LOW
    frequency hum (50HZ) should sound for up to a minute. While this low frequency HUM is Sounding turn the engine on and the HUM should GO AWAY. Now drive your car and see if the low frequency drone has gone away!

    There have been numerous cases where the ANC appears to toggle off all on its own.
    My car started this drone after only 250 miles since new and with NO luck with the dealership I purchased the shop manuals which describes the above diagnostic procedure. It worked for me. Do not change the order of events. Do exactly as printed.
  • I am having same problem. I am on my third Honda Dealer. They are tring to tell me this problem is normal. There is no way. I have become an expert at making the sound occur. it takes a trained foot, and a trained ear. 1500rpm is the magical number, the noise is more prevelant, on the downshift. my mileage is awful, this problem began around 1200miles. I now have 9000miles on my honda accord. Will Honda Ever live up to this?
  • I installed a decent stereo because the factory one sounds very screechy. I thought I'd need the ANC so I put in some relays to automatically switch the speakers between my new stereo and the old one. The car is quieter without ANC! There's almost no noticeable difference in the low frequencies but cutting off the factory radio eliminates a lot of white noise and door rattles.
  • bbyatesbbyates Posts: 1
    Sounded like a good idea and it worked for awhile but it came back the next time I started the car. I guess you would to do it every time you got in the car? I say keep the pressure on and write Honda or fax them and bug your dealer. My dealer looks me in the eye and says, "we're stumped." I don't know if incompetence is the norm now or deceit. Or both.
  • gagricegagrice San DiegoPosts: 31,178
    I don't know if incompetence is the norm now or deceit. Or both.

    I would think it is lack of training and experience with the hybrids. Training these days is short and many times just an interactive course on the Internet. Not much good for indepth training.
  • pacific8pacific8 Posts: 1
    Did the replacement of the speakers fix the problem ? My dealer is currently baffled ( I think they are lying) but recently I think I found the problem not the solution. Its heat related, I live in Los Angeles always above 60 car drones on a trailing throttle, usually at 40 and 60mph, drives everyone nuts, then I drove to Northern California as soon as the temperature dropped beneath 55 and it rained the car became perfect and silent, all weekend it was a delight to drive, now I have returned to LA and the drone is back. My deduction Honda in an effort to bring down the weight ( they had to do this because the batteries are heavy) they reduced the thickness of the body, that vibrates and creates the harmonic when hot, cool it down and add water and it contracts and becomes firm, no harmonic, I am off to the dealer Wednesday with my theory
  • smokey10smokey10 Posts: 2
    I have the same problem--it is better when it is cold and worse when it is warm. No help from the dealer or from Honda Corporate office. I'm meeting with two Investigative News teams today and they are going to do an on air report...I'm tired of the problem. I tried selling it but couldn't because of the noise!
  • smokey10smokey10 Posts: 2
    The dates are old on this chat but if someone searches they may have an answer... I called Honda Corporate and told them about the WBAL I Team doing a report--10 minutes later they "discover" a fix that was put out on March 24th for the loud hum problem... My dealership ordered it and it's being installed this week. Funny how I've been calling for over a year, never getting anywhere, but when a media threat hits they buckle. I'm still doing the interview with the news team--they'll follow it all the way through--including future news pieces if the fix doesn't work--which I think it won't for long... Either way, Honda sucks for not dealing with the problem immediately--I guess people being pissed about this issue cost less than the actual fix.
  • dmathews3dmathews3 Posts: 1,739
    I've noticed that both Honda and Toyota are that way. That is one thing I have never had a problem with on any of my big 3 cars. They all have bent over backward to help if I had a problem.
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