Air Control Valve

[ls400lpg]

Does the LS400 VVTI have an air control valve on the power steering pump?

[ambermarine]

Yes, it is an integral part of the power steering pump on all the ls 400s./430s,its function is to enable the required power without stressing the pump needed to turn the wheel when the car is stationary without increasing engine revs , by using the vacuum created in the plenum chamber. 

[ls400lpg]

Thanks for info.

My power steering pump is making a loud moaning sound when turning steering wheel whilst stationary. Really bad.

[ambermarine]

That is usually the sign of the valve not functioning hence the pump screaming in pain,it can be fixed by removing the valve and blocking the vent to the plenum chamber and this then increases the engine revs but it is not recommended as it changes the take up speed from standstill.the new valves are expensive best option is a  used replacement pump from Paul Frost.

[ls400lpg]

is the valves the plastic thing with 2 hoses attach to it. Thanks

[ambermarine]

Yes

[ls400lpg]

Is it at the bottom of the pump. Thanks

[ambermarine]

Yes.