Strange vibration noise when starting

[ColoRaider]

I have a 1999 4runner limited. I recently started noticing an intermittent noise when starting the truck. It happens as soon as I turn to "ACC" mode and only lasts for about 2-3 seconds and is gone. The best way to describe it is a low vibrating sound similar to the noise your phone might make when vibrating on a table, but at a much lower frequency and a bit louder.
I will try and get some video of it later, but I was wondering if anyone else has had this issue and might be able to help.
Thanks!

 

[gloch]

I think I am hearing this on my '96 as well. Did you identify it?

-gl

 

[Skidmarcx]

Are you hearing the ABS system check?? The module/motor under the hood runs for about 2 seconds

 

[packweco]

I have a 98 Limited, and I have the same sound, but it happens right after I start accelerating the first time after starting the 4runner, every single time. It's a couple clicks and a low groan. I think I narrowed it down to the abs module like skidmarcx said. I can't remember where, but I saw a picture of a page in the owners manual that actually said this noise may be present...

Rather interesting that it happens at a different time on mine.

 

[Baja Runner]

All my 3rd gens have done this, normal sound.

 

[ColoRaider]

It sounds as if is coming from just right of center of the dash. It is odd, I suppose it could be the ABS, but it has just recently started doing this, I assume if it was ABS it would have been present before, right?