Electric motor noise under dash when stopping

[utmba95]

About 1/3rd of the time when I slow down to come to a stop, there is a noise under the dash that appears to be on the drivers side that sounds like an electric motor. It runs at a constant hum for around 3-4 seconds and then stops. It sounds very much like an electric fuel pump. Anybody have a clue what it could be?

This is a 2003 AWD V8. Our 2004 2WD V6 doesn't seem to make that noise.

 

[NOVA46]

That's the master cylinder for your brakes. Perfectly normal.

 

[fdbyrne]

It's the brake accumulator. It's normal.

 

[utmba95]

Thanks! I'll have to check and see if a grommet or plug in the firewall is missing, because my 4runner is much louder than my wife's.

 

[fdbyrne]

Mine got a lot more quiet after I changed out the old brake fluid. I don't understand the inner workings of the unit enough to know if the new fluid actually made it more quiet or if it's a mental thing, though.