Last night I was over at a customers house installing tile. The car had been sitting for about 5 hours then all of a sudden A high pitch whinning almost similar to a car alarm goes off. I could hear it inside over music. As soon as I put the key in the ignition and turned it to ACC the noise shut off. I know I dont have a car alarm. Any idea what could have been making that noise? And what caused it? Thanks

 

Only thing I can think of is the fan. Only thing I know of that can go on when the car is off.

 

Possibly some kind of evap purge.....I've heard of this before, but can't remember exactly what it ended up being. I don't think the fan can come on with the ignition off, and even if it did, ( i.e. if the engine was so hot that the fan needed to stay on to cool the engine) it wouldn't have shut off when you put the key in. It would keep going.

 

the car sat for 5 hours. it was cold i dont think the fan would be in play either. Ive read something about electical noise at random? any ideas?

 

Turbo.

 

...no turbo

 

I would guess evap purge solenoid. The engine was off right?

 

yeah engine off for 5 hrs the car just sat. it was loud enough to wake the neighbors

 

over the 3+ years i've owned my car i have never heard this for myself but people keep bringing it up. anyone got a sound clip?

 

yeah, I think it was the evap purge too.

 

i think its just odd how putting the car in acc mode ended it. it lasted about 5 minutes b4 i went out to the car

 

horn? I can't imagine what would be capable of making noise that loud.

 

EVAP purge isn't a high squeel. It honestly sounds like a cow mooing and only lasts a second or two

 

well i asked a few mechanics i know none had any idea. It was a different sound then the horn. Mabye if it was a electrical load and the horn was getting less power it might sounds different im not sure. still clueless.