2008 Yukon Hybrid is making an loud buzzing noise when autostop kicks in after being driven at highway speeds. Once I come to a stop, autostop engages, loud buzzing noise last for 20-30 seconds, the buzzing is loud enough to hear in the car next me and also I can feel the buzzing vibration through out the truck, appears to come from back. Car appears to run normal otherwise. It started with is doing it every so often, but now does it all the time after driven highway speeds only. Dealer said nothing wrong, yet my truck was not like this when purchased. I've heard it could be the battery fan for the Hybrid. Dealer admitted that with Hybrids they can't do a "trial by error" and switch out parts to try and fix since Hybrid parts are expensive. They yet to duplicate, but I don't think they are testing it at high speeds.

Any idea's?

 

the hybrid has a lot of funky noises that I consider normal. no driveability issues though.

 

IOW could it be the AC compressor or power steering that are both run electrically and could go out of balance?

 

I remember seeing this video a while back: http://www.youtube.com/watch?v=Bkz24zsseWc

Is it the same noise?

 

Serge,
Thanks for sharing the link which I posted few weeks back in another forum.
Yes I get this noise in my Tahoe after a 20 min drive or so in Autostop mode , but it is the auxiliary pump issue the comes out from the front of the vehicle not rear.

http://www.youtube.com/watch?v=Bkz24zsseWc

Anyone else have this noise as well or is it just me?

Thanks

 

I believe it is.

 

I think that is the same noise I'm getting, did your buzzing sound stop after 20-30 seconds? Where you able to get the dealer to replicate and fix? Thanks

 

no it doesnt stop after 30 seconds, but the volume drops somehow.
Didn't take it to the dealer yet, since I was told by some qualified members of this forum, that it is the Auxiliary pump, and GM are aware of it, but it does no harm.
Planning to take it to dealer in the next oil change.
If you manage to take it to dealer and get more info, I would appreciate sharing it with us.
Thanks
Guss

 

Hi gabe,

Yeah this isn't my truck, it's guss' ...

Guss, that sounds pretty awful to me ... hopefully it's not as bad as it sounds but you might not want to wait till next service to have the dealer see it.

Cheers!

 

Hello Guzz-

I wanted to follow up and see if you had your Tahoe Hybrid serviced yet and any fix to this buzzing noise?