I was installing my exhaust this weekend, and while we worked, I had the key in the ACC position so we could listen to CDs while we put it on. Well, when the key was in that position, there is a slight high pitched tone that comes from somewhere in the engine bay. Not sure where, but it's very definitely there. When I clicked the key back one notch, where the cd player works, but the console isn't lit up, the noise goes away. Any idea what this could be? All other accessories were off, like AC, etc.

2004 5AT Coupe | Black Obsidian / Willow | Prem | Borla Exhaust | JWT Pop & Z Tube | CC | PIAA | Aluminum Pedals | 20% Tint
http://www.cardomain.com/memberpage/543698

 

??? just throwing it out, fuel pump. maybe you can hear the fuel flowing through the hoses, regulator and back into the return line (if this car has got one). Just got mine and haven't given it the through look through yet. But in other cars the fuel pump is running if it's left in ignition.

 

I don't think it's anything like that. I wonder if maybe there is something wrong with the alternator or something. It definitely sounds like an electrical issue. Can somebody else turn their ignition to ACC and roll your window down? If you hear the same high pitched tone, maybe it's a common thing...If not, I may need to take it to the dealer.

2004 5AT Coupe | Black Obsidian / Willow | Prem | Borla Exhaust | JWT Pop & Z Tube | CC | PIAA | Aluminum Pedals | 20% Tint
http://www.cardomain.com/memberpage/543698

 

I read your post & turned my ignition to ACC and listen for about 30 seconds for the noise your described. I have "no" noise coming from my engine compartment. I lifted the hood & listen. No fuel pump noise either. I have a '03.5 coupe 6mt. Hoped that helped.

 

The noise is "normal". I heard it as soon as I got my car new and took it back to the dealer. The Sales Manager and I went to other G35s and turned the ignition to the second position and the hum is there. You have to really listen closely and it's easier to listen outside the car. Trying to listen for the hum inside is hard because of all the insulation.

Nothing to worry about.