What is this noise?

[pissedoffgokart]

Please move if not in proper topic!My parents have a 2006 Auto Vibe in Ohio and it is apparently humming. My dad said he went into the garage, 4 hours after the car was driven last, and heard a humming sound (he described it as a neon sign type sound) coming from the rear underside of the car. It stopped within a few minutes, and he has only heard it a few times. He said it wasn't loud by any means and thinks it would be inaudible outside of the garage. The dealer told him it was normal and that it was an oxygen test that the car periodically performs. Due to the rapidness of his response my father believed him. I suppose it could be emmissions related, but sounds strange.Why would the car do an oxygen test 4 hours after being driven? Anyone know?

[joholste]

I don't know why that would be or if our cars even do that....but it could be the sound of a pissed off gokart maybe?

[Mavrik]

well if he came in while the car was hot and shut it off... perhaps a cooling fan? I've never heard any humming sounds from mine.

[ToolGuy]

The dealer is probably right! Most likely...Some of today's cars have an automatic EVAP system test for leaks and the test can come on at any time and when the car is not being driven. I can see this as being annoying and hope the noise does not get louder as time goes on. GM/Toyota must have changed to this type of system as the new Vibe model years got introduced.

[pissedoffgokart]

joholste:It might be if it were MY car, but alas it is the parents. Mav:I'm too close for missles, switching to guns Sorry, I had to. Anyway, it hadn't been driven for 4 hours, and the sound was from the rear! Just think of the evile I could do with a fan at the rear....Mi-Vibe:That is just C R A Z Y if they did something like that! I suppose I could call the dealer my darn self, but these crooks out here would tell me to bring it in so they could charge me!Thanks for the responses so far!!

[dianebrat]

I have an '06 AWD and there's a notice in the owners manual stating just that..It can make noise in the rear of the car for a test several hours after being stopped.I'm not at home so I don't have the exact syntax, but it's normal.Diane

[pissedoffgokart]

Thanks all, I will make sure and force pops to read the manual!!! Used only as a last resort normally and has been known to cause death to a man.!!!

[Danielstiel]

I read it in my manual, I have a 2006, it is a Oxigen test, but actually it has something to do with the gas, pressure realease.

[Botany]

I know the beginning of this post is nearly three years old, but the same thing happened to me last night.In the evening I stepped into the garage and heard a faint humming noise. I quietly listened and thought it was something outside. I checked outside, but it wasn't from there. I thought it may be something vibrating in the garage, but again I found nothing. I squatted next to the back of my 2007 Vibe and it sounded like it was coming from the car.Back inside, I told my wife about the noise and she said she has heard something similar.Thanks for the past postings; helps explain the noise. My car was off and had been so for ca. 5 hours when I heard it. The noise stopped after a few minutes.