GS300 buying check.

[Birdster]

Looking at a GS300 series two and found something online saying to pump the brakes when stationary to test. After a test drive I pumped the brakes a number of times, audible warning and VSC OFF, ABS and VSC lights come up and go away after a little while. I couldn’t hear the pump due to the engine fan (warm day and did seem to come on and off as expected) and I don’t have the best hearing anyway. I tried this three times with the same result of lights and sound warning. From googling it suggests that the brake booster is a common issue with GS300s but this is when the lights and audible warning come on randomly or under certain driving conditions. So just wanted to check if this is anctual test of the brakes/booster and if this a car that needs a new booster or could it be something else or have I carried out a reset procedure or system or something?

Thanks in advance.