2001 Toyota Corolla - High Pitched Hum

JPP412

MEMBER
2001 TOYOTA COROLLA
4 CYL
FWD
AUTOMATIC
56,000 MILES

I have a 2001 Toyota Corolla with about 56000 miles on it. Never have had any problems with it to speak of and in particular no recent unusual problems.

Yesterday when I got in the car I noticed a high-pitched hum - without even starting the car! After starting the car the hum persists - also does not change based on speed or anything.

No lights on, nothing plugged in to the lighter, turned the dome light off, etc. Also I checked under the hood to see if it was coming from there somehow and, no, it is not.

Of course, at first I thought it was just my ears ringing or something - however this noise has been verified by my wife and my 2 kids.

I have googled various ways and cannot find anything on the internet about this.

Any ideas anyone?

Thanks in advance for any help!

- Joe

2 Replies

MMPRINCE4000

MECHANIC
8,548 POSTS

Could be a EVAP purge valve that is stuck.

I would check the relay box, any relay that is warm or hot would indicate a stuck relay.

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Friday, February 11th, 2011 AT 1:26 PM

JPP412

MEMBER
2 POSTS

Thanks for the quick reply. I can't find the relay box - where is that located?

The sound is definitely originating from near the firewall on the driver's side. On further investigation I can hear it with the hood open if I put my ear down near the firewall on driver's side - but not nearly as loud as in the car so I assume it is originating from inside the car.

The evap purge valve is located above the gas tank is it not? If so could that really be a possibility considering the sound originating near the firewall?