spicedsp03 Report post Posted August 7, 2013 I notice this Loud Buzzing noise when opening the door and/or first turning the car on. What is this noise? Sounds like something is moving under the hood... Quote Share this post Link to post Share on other sites
corncobs Report post Posted August 7, 2013 Probably the active grill shutters. Quote Share this post Link to post Share on other sites
hybridbear Report post Posted August 7, 2013 The FFH doesn't have a vacuum brake booster since the ICE doesn't run all the time, you're hearing a pump building up pressure for applying the brakes. Try sitting in the car and stepping on the brake pedal a few times. You should hear this noise when you do that confirming that it's the brake vacuum pump. 1 GrySql reacted to this Quote Share this post Link to post Share on other sites
SteveB_TX Report post Posted August 7, 2013 The FFH doesn't have a vacuum brake booster since the ICE doesn't run all the time, you're hearing a pump building up pressure for applying the brakes. Try sitting in the car and stepping on the brake pedal a few times. You should hear this noise when you do that confirming that it's the brake vacuum pump.Doubtful. Mine makes the same buzzzzzzing sound the OP is talking about. Neither the grill shutters or brake pump do anything until you start the car. We get the buzzing sound from under the hood just by opening the door. It sounds like a relay opening and closing multiple times very quickly. I figured it was just another odd hybrid sound. :) Quote Share this post Link to post Share on other sites
aaronj1159 Report post Posted August 8, 2013 Doubtful. Mine makes the same buzzzzzzing sound the OP is talking about. Neither the grill shutters or brake pump do anything until you start the car. We get the buzzing sound from under the hood just by opening the door. It sounds like a relay opening and closing multiple times very quickly. I figured it was just another odd hybrid sound. :)Yeah I get it too. Although I should add that my dad's BMW (non-hybrid) does this too. Quote Share this post Link to post Share on other sites
hybridbear Report post Posted August 8, 2013 Get in your car but leave it off and pump the brakes. I'm pretty sure the brake pump operates independently of key position. When you unlock the car and open the door the car is preparing to have you get in and apply the brake so it's building pressure. When the car has been sitting for hours there is no pressure remaining in the system so it needs to build up pressure. Doubtful. Mine makes the same buzzzzzzing sound the OP is talking about. Neither the grill shutters or brake pump do anything until you start the car. We get the buzzing sound from under the hood just by opening the door. It sounds like a relay opening and closing multiple times very quickly. I figured it was just another odd hybrid sound. :) Quote Share this post Link to post Share on other sites
smr2112 Report post Posted August 8, 2013 If we're talking about the same thing, I tend to hear that as I pull into my garageat the end of the day. Coming from front area, so likely the grill shutters, butwhy when I pull in the garage? Lasts about 2-3 seconds and sounds like somethingmotorized. Quote Share this post Link to post Share on other sites
acdii Report post Posted August 9, 2013 Its the brake pump. I can get mine to make that noise at any time just by playing with the brake pedal. Quote Share this post Link to post Share on other sites
expresspotato Report post Posted August 16, 2013 I agree its the brake pump - the active grill shutters are virtually silent - pieces of plastic moving really slowly an inch don't sound like that Quote Share this post Link to post Share on other sites
