When I turn the ignition ON (but not start the vehicle), after about 15 or 20 seconds a little motor in the back of the Escalade starts running and the sound is fairly loud.

The sound comes form the vibration of the motor as it is running. I can put my hand on the little motor and feel it vibrating.

The motor is mounted BEHIND the driver side rear wheel, about 1 foot below the gas tank fuel point.

I did a quick trace of the lines form the little motor I am wondering about. First of all, the lines are rather fragile, I believe they are vacuum lines. One line runs up to a small triangular module mounted around the fuel cap. Another line runs from that over to the differential gear box on the rear axle and appears to terminate there.

After about 2 minutes or so, the motor stops running and it may not start back for some time.

I have ODC codes of p0452 and p0446, having to do with the evaporative venting system. I can clear those codes and they may come back immediately or after a little while. I have no idea of those codes are related to that little buzzing motor.

I have had this 2003 Escalade for about a year now and it has always made that sound. It's not terribly loud but it still seems odd because I have never heard a vehicle make that sound before.

Any ideas on what that is?

Thanks!

 

Bump. Surely somebody can help.