This test checks independently of engine operation whether the electrical vacuum pump is able to supply the partial vacuum necessary for braking power assistance.
The vacuum pump is activated for a maximum of 20 s. At the start of the system test, the partial vacuum must not fall below the value of -300 mbar. If necessary, the partial vacuum must be reduced accordingly by pressing the brake pedal.
As soon as the partial vacuum falls below the value of -500 mbar, the test is regarded as OK.
The run conditions for the system test are: