LOW FREQUENCY NOISE - GreenHybrid

Dataagej · #1 (**permalink**) 06-19-2006, 09:32 AM

HAS ANYONE NOTICED A LOW FREQUENCY SOUND COMING FROM THE ENGINE AT AROUND 1600-1700 rpm'S?
AT FIRST I THOUGHT IT WAS COMING FROM A CAR DRIVING NEAR ME. IT SOUNDED LIKE THEY HAD TURNED UP THE BASE REALLY HIGH. IT HURTS MY EARS NOW AND ALMOST SHAKES THE WINDOWS! i'M TAKIN IT IN TOMORROW TO THE DEALER SO I'LL LET YOU KNOW WHAT THEY SAY. THEY HAVENT HEARD ANYTHING LIKE IT BEFORE.

JOHN

gonavy · #2 (**permalink**) 06-19-2006, 10:48 AM

- please don't use all caps. It is very hard to read.

Where were you driving? Did it persist? Can you repeat it all the time, on different road conditions? Does one of your mufflers have a hole?

A low rumble I have not heard. There is often a high-pitch whine that is characteristic if the IMA, we think.
If it sounds very bass-y you are not hearing 1600Hz directly- more like a subharmonic or a low engine resonance that is getting excited there.

If I had to guess, based on no other information, the active noise suppression is not functioning properly at that engine speed, and sending the 'wrong' noise through your speakers (even with radio off it is active). That is asusming it wasn't road noise or some other external wierdness.

Please let us know what the service dept says!

Dataagej · #3 (**permalink**) 06-19-2006, 11:16 AM

Sorry about the all-caps... I could hear the bass-noise all day driving saturday but today I can't get it to reproduce. simple driving conditions, no hole in muffler or any external wierdness or road conditions... it's coming from the engine and it sounds like it's being transmitted through the bass in the speakers (which were turned off). I'll let you know tomorrow what the dealership says, thanks for the idea about the active noise suppression.
John

gonavy · #4 (**permalink**) 06-19-2006, 04:40 PM

through the speakers.... my finger is definitely pointing at the noise suppression

mikemc · #5 (**permalink**) 06-19-2006, 06:28 PM

I have a 2005 Honda Accord Hybrid (bought Nov 04) with just over 10,000 miles on it and have also been experiencing a loud, low frequency rumble when the engine is at about 1600-1700 RPMs in ECO mode (3 cylinder operation). I suspect that when in 3 cylinder operation at low RPMs that the resonant frequency of a major component of the car is reached and that the sound dampening becomes ineffective. Or, perhaps there is something wrong with the active noise cancellation technology or the active engine mounts. I haven't yet had a dealer look at the issue.

Dataagej · #6 (**permalink**) 06-20-2006, 11:23 AM

Hello all,
My local Honda dealer, based on the information I gave them from this forum, was able to find and fix (part's been ordered) the problem. They said it was a TSB (technical service bulletin) from Honda and a quick test was able to identify the issue to be a faulty active noise suppression coming through the front speakers. He said they hooked a wire to an area by the dome light and the other end went to a ground. The test failed immediatley and Honda does recognize the problem.
Thanks again for all your help smart people.

gonavy · #7 (**permalink**) 06-20-2006, 06:05 PM

great! I'm very glad we could help, that we were right (for a change), and that Honda is taking action.

nimbus2k · #8 (**permalink**) 07-07-2006, 04:34 PM

I had this go out on my 05 HAH this week and was VERY glad I read this thread here because I was the first one to hit my dealer with this problem.

Fortuntaely (I guess) in addition to replacing the faulty noise supression unit, they also replace the radio speakers because the chances are pretty good you've blown the bass in your speakers. (the only way I can describe the sound is like driving over those "barking strips" on the freeway, only 10x louder.

If anybody needs to go to their dealer about this, the service bulletin number is: 06-005

Elle · #9 (**permalink**) 07-10-2006, 11:47 AM

I too am experiencing this noise so I called the dealership and they had no idea what I was talking about. I refereneced the TSB 06-005 and the guy on the phone just asked me to bring the car in and show him the noise. I am not sure how well he will be able to "see" the noise but I will try I guess. I was wondering if anyone could tell me how or where to get a copy of the bulletin to take with me to the dealership.

Thanks,
Elle

nimbus2k · #10 (**permalink**) 07-10-2006, 04:21 PM

I think the service bulletin mentions something about a test that the dealer can do in the shop to see if the unit has failed, so you shouldn't have to show them anything (though it would be sort of fun to get them in the car, start the rumble and then say "can you hear it NOW?"