I am looking to buy this 99 GS300 from a dealer but when I turn the key to the "on " Position, I get this pumping sound, and then after like maybe a couple of minutes it shuts off. Just getting an idea what it is and is it a cheap fix? Thank for the help guys.

 

egg-

do a search in gs 3-4 (suspension brake) section on master cylinder. It makes that noise on start up, and this is quite normal. Anybody else wish to chime in?

Did u drive it??

 

I believe this is normal for the GS's . It's system check for VSC system.

 

It's not for the VSC. It's the brake booster pump pressurizing the system. It's normal for all GS's. These care have an electric booster pump rather than the more common vacuum assisted booster. The upside is that in the event the engine stalls out, the brakes will still work 100%. On a car with vacuum assist, if the engine stalls out...the brakes lose power significantly.

 

I've heard this noise sometimes when I'm braking while coming to a stop

 

If you were slipping a little or going over a bump while braking that might have been the ABS Pump.