slight squeal / air escaping noise

[tlaine]

It happens when I am slowly coming to a stop. I am pretty sure it happened the other day when I was pulling into my driveway. And I am almost certain it has happend when I start to accellerate after sitting at a redlight, but I've been under so much stress lately I cant really remember.

I can tell you exactly how it sounds though and I was wondering if anyone else has heard this or had this problem.

It sounds exactly like your holding the mouth of a balloon taunt and slowly letting the air escape. It's a quiet sounding high pitched squeal I guess you could say.

My '08 never did this. And my '09 has only started doing this in the past month or so. I cant hear it when I have the radio on, so it's not loud enough to be noticable unless it's quiet in the car. It's hard to pinpoint where it is coming from.

We've left the car with the dealership now, and I havent heard what they have to say about it. But the Tech was really good and didnt make me feel stupid for how I was describing it. Anyways, if anyone else has heard a sound similar to this, I'm curious to see what it could possibly be.

[richard schumacher]

That description sounds a whole lot like the sound made by the electric drive and battery management systems. It's completely normal. It just takes some little mechanical part somewhere that happens to resonate at the same frequency to make it much more apparent, so it's not surprising that you might hear it in one car and not another, or at one time and not another.

[tlaine]

There is an electronic hum that I do normally hear when accellerating and decellerating.

This sound is different though and I can confirm that yes it does do it when I slow speed break and come to a stop, and when I just start to accellerate after being stoped for a moment or two. And the sound dosen't last long, just a second or two and then stops, and it dosent do it every time, just occasionally. And from what I can guess, it sounds like it's coming from infront of me, possibly down where the break and gas pedals are.

I got my car back from the dealership and of course, they couldnt duplicate it, and what they did check is working normally. Still makes the sound. The car just hit 10k miles and it only started doing this the past 3k miles I guess.

Thanks for the replies =)

[Bob64]

I've noticed it on my car too. I think its coming from the inverter?

[richard schumacher]

That'd be my first guess.

[tlaine]

actually upon further listening for the noise, it's coming from the back seat, where the battery vent is, probably from the battery area. Is that still normal?

[richard schumacher]

Presumably you had a friend crawling around inside the cabin to confirm the source while you were driving it? (Forgive me but I don't believe that anyone can reliably pinpoint the sources of most noises inside this car while driving it.)

Anyway, assuming that it is coming from the battery vent, then it's new to me. If the dealer can't reproduce it and if there are no trouble codes or warning lights then it could be very difficult to diagnose. But if there are no trouble codes and no warning lights then it's probably normal and not the symptom of any problem.