so I was wondering if anyone could help me. I bought a 05 hybrid in November and haven't driven it regularly until i got out of school a week or 2 ago. Now that im driving it everyday Ive noticed that when I am driving with the windows up and radio off there will sporadically be very a very deep noise produced by the car. It sounds just like a very loud bass coming from the speakers and even rattles my door. If i step on the gas a little it immediately goes away.....It happens both when i have my foot on the gas and when I have it off the gas and im coasting.......ANY IDEAS???

 

I just registered here to see if anyone else had any resolutions to this. I've got the same exact issue and I've heard of it happening before, but no one has a known resolution. I've also narrowed it down and can repro it on demand. It happens right at around 1600rpm in any gear, when in ECO mode and simply cruising. If you accelerate or aren't in ECO mode, it won't do it. It seems to me it's got to have something to do with a vibration from running on 3 cylinders and it just creates a certain frequency that runs thru the whole car like a tuning fork. No problems with the car at all beyond this annoyance. Hopefully someone will know about this and exactly what's wrong, as it's such a unique issue and only occurs with the Accord Hybrid, it's a defect of some kind.

 

I think clay probably has the answer. running on 3 cylinders and transmitting the vibration through the car.

 

Actually, I found the issue. Honda's technical support bulletin 06-005 describes the problem. It's a failure in the active noise cancellation setup. Just like the Bose sound reducing headphones, there's a setup in the car that will tune out the sound with the front speakers. The "bass sound" actually is normal and it's not anything breaking, you're just not supposed to hear it.

Honda will most likely cover the parts, but out of warranty customers (which is most of us) will still have to pay labor. If you get parts covered, labor should run around 150.