Check the vacuum pump for leaks

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.

Fig 1: Checking Vacuum Pump For Leaks

Courtesy of VOLVO CARS OF NORTH AMERICA.

Check the vacuum pump for leaks by blocking the hole in the adapter with a finger and pumping out the air. There should be no increase in pressure.

Repeat the above, this time with overpressure. There should be no reduction in pressure.