Checking the output of the electric auxiliary pump

Fig 1: Identifying Special Tool

Courtesy of VOLVO CARS OF NORTH AMERICA.

Plug the open connection of the T-valve.

Connect special tool 999 5230 to the vacuum hose.

Start the engine.

Check the output of the electric auxiliary pump.

Negative pressure 35 - 45 kPa	Electric auxiliary pump does not run	System OK
Negative pressure > 45 kPa	Electric auxiliary pump activated	See Checking the electric auxiliary pump system for leaks
Negative pressure > 45 kPa	Electric auxiliary pump does not run	Replace pressostat
Negative pressure < 35 kPa	Electric auxiliary pump does not run	Replace pressostat
Negative pressure < 35 kPa	Electric auxiliary pump activated	See Checking the electric auxiliary pump system for leaks

If the pump runs continually even though the system was checked and the pressostat replaced, replace the electric auxiliary pump. See Removing and installing the electronic accessory pump assembly .