2 to 3 Second Buzzing Sound at Start up

[dangerruss]

I own a 2012 Rubicon JKU with 38,000 miles on the odometer. I have recently experienced hearing a buzzing sound coming from underneath the hood at start up. The buzzing sound does not happen in the mornings… only late afternoon. The buzzing sound last 2 to 3 seconds and only happens when the jeep has been sitting for several hours and it’s above 90 degrees outside and at best is intermittent. There are no error codes being reported by the computer. The buzzing sound is like an old fashion buzzer. Anyone else experiencing a similar problem?

Thanks,
Russ

 

[bo9roadking]

Not sure if this is actually a problem. I get the same sound when my 2012 has been setting for a while. It is the vacuum canister for the brakes. It acts like it is charging when you first apply the brakes after the Jeep has been setting for a while. Once it is charged, the sound goes away.

 

[olram30]

Not sure if this is actually a problem. I get the same sound when my 2012 has been setting for a while. It is the vacuum canister for the brakes. It acts like it is charging when you first apply the brakes after the Jeep has been setting for a while. Once it is charged, the sound goes away.

my '12 did that also, when i had it under my hood i could really hear it. moved it back out of the hood because it bugged me.:idontknow:

 

[TheDuff]

There is a servo in the trans that can be rather noisy. I've heard mine before. I you Google for it you may be able to find a YouTube vid of it and see if it matches the sound you are hearing

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