S60, help to identify component

[importCar]

Hello, could someone kindly help me identify the round aluminum look part in the center of the photo?

Also, when starting cold, this thing will buzz. Is it normal?

Thank you.

[jbeebo]

That's an electric vacuum pump. For turbo engines, which don't always have negative intake manifold pressure it's required to provide vacuum for the brake booster. For some reason they use it for the normally aspirated engine too. Mine makes noise on startup and each time I step on or release the brake pedal. http://www.volvopartswebstore.com/showA ... lYear=2005

[jimmy57]

variable valve timing is why they used it. Turbo or not, the cold start emissions reduction process using dual CVVT and ignition timing retard takes intake vacuum to a very low level. Altitude makes it even worse. Turbo engines do go to pressure in intake under boost but when you idle or lift off throttle to apply brakes the intake goes vacuum again. The adjusting of cam timing together with retarded ignition timing is the difference that could leave you with a rock hard brake pedal and poor brakes.
Single CVVT also suffers from low vacuum until cam timing is returned to normal control once the engine warms a little.

So, yes,it is normal to hear the vac pump run on a cold engine when you depress and lift off brake pedal. The two wire connector you will see on a round device T'd into vac hoses and attached to air cleaner housing (under the blank spot cover on 2004-2007 R's) is the switch that turns on pump when vacuum level in brake booster supply hose falls too low. If it runs continuously when cold when you have not touched brake pedal then another problem exists. Leaking brake booster, leaks in vacuum lines to brake booster, or even a problem with the switch could make it run continuously at times.

[importCar]

Thank you so much for the answers. The first buzz in the morning happens when i depress brake for shifting in gear.

This might also confirms one thing: there is leak in the intake path. I still not identified location yet. Still getting P0101 code.

Really appreciate your help.