captaineddie Posted November 25, 2012 Report Share Posted November 25, 2012 I just walked through our garage and heard a buzzing sound coming from the back portion of the car. It's a little bit like the noise an electric fuel pump makes. I started the car and then turned it back off and now it's not making the sound. I'm going to check with the service manager Monday morning and hope the noise doesn't start back up again and run down the battery. Anybody got a clue what it was? Quote Link to comment Share on other sites More sharing options...
dtorres Posted November 25, 2012 Report Share Posted November 25, 2012 (edited) Same thing happened to me yesterday. I seem to recall from the owners manual that it's the fans for the hybrid battery. They can stay on after the car is turned off to cool the high voltage battery. I noticed it after pulling into my garage. Five minutes after turning the car off I could still hear them. Concerned about battery run down I did the same thing cycled the ignition on and off and the noise stopped. Edited November 25, 2012 by dtorres Quote Link to comment Share on other sites More sharing options...
dtorres Posted November 25, 2012 Report Share Posted November 25, 2012 Page 184 in the manual describes the noise from the rear of the vehicle : "The fan noise comes from a fan located inside the high voltage battery. This fan turns on when the battery requires cooling air. The fan speed, and associated noise level, will change according to the amount of cooling required to maintain good performance. Maintaining the battery temperature at optimal conditions also prolongs the useful life of the battery and helps to achieve better fuel economy. " Quote Link to comment Share on other sites More sharing options...
erwhitham Posted November 25, 2012 Report Share Posted November 25, 2012 Yes, hybrids tend to talk. My third and this one seems to be the quietest Quote Link to comment Share on other sites More sharing options...
captaineddie Posted November 25, 2012 Author Report Share Posted November 25, 2012 You're probably right about the fan. It happened, though, when the battery should've been cold. The temperature outside was 27 degrees and the garage didn't feel a lot warmer! Quote Link to comment Share on other sites More sharing options...
RachelnLa Posted November 25, 2012 Report Share Posted November 25, 2012 If you just shut off the car then the battery itself is warm and may have needed cooling. My Tahoe has some blower that kicks on after the truck is off. It's to dry up any condensation in the ac lines. Scared the bajeezus outta me the first time I sat in the truck after turning it off and that blower kicked on. Quote Link to comment Share on other sites More sharing options...
Generalbeluga Posted January 16, 2013 Report Share Posted January 16, 2013 (edited) There is also a buzzing sound coming from under the hood area when the car is first started. I thought this was a sound added so sight impaired people would be able to hear the car. I believe Toyota had to add something similar to the Prius a few years back after some run-over accidents. Edited January 16, 2013 by Generalbeluga Quote Link to comment Share on other sites More sharing options...
FoutsNC Posted January 16, 2013 Report Share Posted January 16, 2013 (edited) There are no noise producing options on the current C-Max for the vision impared. The US DOT has proposed new sound requirements that will most likely be seen on future models. It looks like a speaker will have to be installed under the hood and a device to make a sound that the manufacturer sends to it. http://www.dot.gov/briefing-room/us-department-transportation-proposes-new-minimum-sound-requirements-hybrid-and Personally, I really like the stealth option with this car. My awareness of people walking in parking lots and such is much higher than it used to be. I am sure we have all seen the surprise on people's faces when we pass them silently when they didn't know we were there. I wonder what manufacturer will be using the Jetson's sound to differentiate their hybrids Edited January 16, 2013 by FoutsNC CNCGeek 1 Quote Link to comment Share on other sites More sharing options...
valkraider Posted January 16, 2013 Report Share Posted January 16, 2013 First thing I do is disconnect that speaker and if the car complains wire an equivalent resistor in line so it thinks there is a speaker there. Stupidest law ever. Legislated noise pollution... FoutsNC 1 Quote Link to comment Share on other sites More sharing options...
Bill-N Posted February 3, 2013 Report Share Posted February 3, 2013 I just walked through our garage and heard a buzzing sound coming from the back portion of the car. It's a little bit like the noise an electric fuel pump makes. I started the car and then turned it back off and now it's not making the sound. I'm going to check with the service manager Monday morning and hope the noise doesn't start back up again and run down the battery. Anybody got a clue what it was?I just had this happen. High today was about 25F. After some errands, car was left outside in front of the garage from about 3:00pm until 6:30pm. I then put it in the garage and turned it off. So far, so good. A few minutes later, I returned to the garage and heard the buzzing. Could have been a fan, but at rather low speed. Sounded somewhat like a bicycle with a playing card in the spokes. But not too loud. Note, the garage is unheated, and it took all of 30 seconds to move the car into the garage. No way the high voltage battery needed cooling, and without the engine running, there's no source of heat. Anyway, I got in the car, put it into accessory mode (i.e. "start" but without foot on the brake), then turned it off. Buzzing stopped. All very bizarre. I wonder if this is a precursor to a dead 12V battery? Quote Link to comment Share on other sites More sharing options...
roninsd Posted February 3, 2013 Report Share Posted February 3, 2013 This happened to me once a couple months ago, but no dead battery followed. Quote Link to comment Share on other sites More sharing options...
Chinto Posted February 3, 2013 Report Share Posted February 3, 2013 I have had this noise occur once last month. No idea what it is but it stopped after starting/stopping motor. Sounded like a switch openning & closing very rapidly. Quote Link to comment Share on other sites More sharing options...
Bill-N Posted February 3, 2013 Report Share Posted February 3, 2013 This happened to me once a couple months ago, but no dead battery followed.Did the noise stop by itself? Quote Link to comment Share on other sites More sharing options...
fotomoto Posted June 1, 2013 Report Share Posted June 1, 2013 I'm pretty familiar with the extra sounds hybrids make compared to a traditional car but this buzzing sound was a first for me. I heard it in my closed garage a couple hours after driving. I became concerned when it didn't stop after a few seconds like most other hybrid sounds. So, I went back into the house, got my camera phone, came back out to the garage, crawled underneath the rear end of the car and recorded a couple of videos about a minute each. It was still going when I went back in the house. I went back out about 10 minutes later to check the 12v voltage and it had stopped by then. Voltage was OK. Sounds like the fuel system doing some kind of priming/purging: Oh, and excuse the grunting. :hysterical: The floor was dirty and I was trying to keep my hair out of it. :baby: Quote Link to comment Share on other sites More sharing options...
Bill-N Posted June 1, 2013 Report Share Posted June 1, 2013 As I noted in another forum: "I and several others have noticed this. I'm guessing it's the C-Max performing fuel system evaporation leak test(s). These apparently need to be done after the car sits awhile so there is no pressure inside the fuel system. There's some mention of these tests here (http://fordcmaxhybri...ne-light/page-4) that may help." Quote Link to comment Share on other sites More sharing options...
fotomoto Posted June 1, 2013 Report Share Posted June 1, 2013 (edited) Yeah, I saw that post earlier today which reminded me to finally upload the video for others and post it in a related thread (albeit old). That link of yours is to a CEL/fuel inlet thread which really doesn't have anything to do with this buzz noise. I have no issues or CEL and haven't heard the buzz since. Edited June 1, 2013 by fotomoto Quote Link to comment Share on other sites More sharing options...
ScubaDadMiami Posted June 1, 2013 Report Share Posted June 1, 2013 Yes, that's the noise! I only heard it when I was in EV with a window open, when I first started up. I haven't heard it when leaving, though I have my C=MAX for less than a week. Quote Link to comment Share on other sites More sharing options...
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