What noise could a CPU make? an OBD? <_< an FTM?
Inquiring minds want to know....although I suspect CPU's don't make any noise.

 

I noticed that the DVD drive that runs Nav is whiring once the keys are in the ignition. Actually, it may even start the moment I open the door, even before the key gets in the iginition. It may be trying to get a head start since Nav and probably Idrive need some time to boot up and gather up the data before being ready to work. There is possibly a hard drive for Idrive that has to spin to off load data each time.

 

SMG owners, here's some better proof of the old theory that the noises you hear upon unlocking the car (wakeup) is some hydraulic pump for the clutch...

From TIS:
Engine start
To start the engine, the gear lever and transmission must both be in "N" (neutral). When the engine is started, sufficient system pressure must immediately be built up to open the clutch. For this reason, the SMG control unit is activated by a wake-up signal from the car access system (CAS) when the vehicle is unlocked. The SMG control unit measures the system pressure via the hydraulic pressure sensor. If the system pressure is too low, the hydraulic pump will be actuated. The hydraulic pump will build up pressure. When the system pressure has been reached, the SMG control unit will switch the hydraulic pump off again. With the "wake-up signal", the gear lever position indicator in the centre console is activated. If terminal 15 (wake-up wire) has not been activated approx. 15 minutes after the vehicle was unlocked, the gear lever position display will be switched off again.

 

Way to go, Rudy!

Now, what is that little sound that sounds like someone sat on an egg shell in the next room? It may be iDrive accessing something, but I'm not sure what. I think it also has a connection with SMG.

 

Be aware that backup copys of the NAV DVD skip like hell. At least from my experience!