Throttle body - high pitched whine (not loud)
 

So I played around with my Boxster trying to figure out what the whining noise was and I figured these things out:

1. The noise is coming from the throttle body, or something close to it.

2. If I turn the key to the position just before it starts the motor (all electronics on), the noise is there. If I wait about 10 seconds, the throttle body makes some other noises for a second or two (something adjusting itself inside). If I turn the car all the way on after I make the throttle body adjust itself, there is no high pitched noise. But if I don't let the throttle body adjust itself, the noise is present until the car warms up.


Strange, right?

Anyone experience this noise?

Sounds like the secondary air injection pump.
It adds extra air for the emissions until the cats warm up, then it shuts down.
Happy Boxstering,
Pedro

Could it be that even if the noise happens when the engine is off?

I'm pretty sure the noise is electronic, almost like the noise a microwave makes when the timer goes off but nowhere near as loud.

I hear the noise when the key is turned to the position before turning the motor on.