Install the Control Valve
WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Replace the power steering pump if the read off values do not correspond with the specified values even after repeated diagnostic testing. See Removing And/Or Installing the Power Steering Pump, Gasoline Powered Cars .