Buzzing noise under bonnet after switching off
 

Hi anybody know what could be causing my xc60 to have loud buzzing noise under bonnet after switching off. Lasts just under a minute. No dtcs, drives ok.
Also when switching aircon on and off when running get squealing noise which goes. Is this the stretch belt slipping so needs replacing.
Thanks Mark

Sounds similar to my car, when the throttle valve actuator was faulty. See the thread below.

https://www.volvoforums.org.uk/showthread.php?t=293282

I read an error code using my OBD scanner at the time which confirmed the issue before I took it to my local dealer.

My V60 Polestar air con compressor emits a permanent hum when everything is switched off. No idea why, but must use power. Battery drain on that car has been an issue since new. The electrical system on the 2015 era S/XC/V60s seems a bit bizarre; something that stopped us buying an XC40 for a second car that my wife would use.

Bought a Mazda CX30 instead; with a totally gutless 2.0 litre, uneconomical SkyactiveX engine. 35 mpg at best, marketing hype over reality.

Mine's done the noise when switching off for probably over a year now. I did research it at the time and it seemed to be relatively common but I concluded it was nothing to worry about.

I think its probably the throttle body stepper motor sticking when trying to find closed position for starting, not 100% sure though. Maybe give it a clean if does it again. As theres no fault code and it only does it every now and then, will just keep eye on it

Mine does this too as does the Volvo my local Indy drives. Probably just a 'feature' of how it shuts down.

Yea my 2015 xc60 has always done this

Mine too, from new.