[spaceman2844]

Originally Posted by Mark purdz

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.