W208 buzzing sound from air intake pipe

[the prince]

Just wondering if a buzzing sound from air intake pipe is normal. When i turned ignition key to '2' i could hear a buzzing sound coming from engine. On closer inspection it appears to be coming from the air intake pipe / MAF area. Is this normal on W208 230k's? I've recently just had the battery on charge and only noticed this when i hooked the battery back up again.

I know this may sound trivial or minor, it's just i've just got this car and seem to be finding all sorts of new issues idiosyncrasies which i'm not familiar with. The car seems to start fine and start / idle ok, if slightly wavering, but no misfire. The buzzing is still there when engine turned off, but again only when on 2

 

[Will]

Maybe the motor for the electronic throttle?

 

[the prince]

Maybe the motor for the electronic throttle?

Is it normal to hear this on turning the ignition on?

 

[rorf]

Quite normal - lots of electronics under the hood. If car runs well then leave well alone, no tinkering

 

[the prince]

Quite normal - lots of electronics under the hood. If car runs well then leave well alone, no tinkering

Cheers.

No tinkering is sound advice.

As my other cars are all generally old and simple fixes when anything goes wrong, owning the W208 causes a sense of anxiety whenever i happen to notice something new. A buzz, rattle or light on the dash certainly gets my attention, whereas my old trusty 205 diesel just chugs along with it's squeaks and rattles without missing a beat. Exciting it most definitely isn't. Reliability to a boring level and 60mpg on an average cycle has been the reason for ownership.