System Test For Electrical Vacuum Pump MSS65

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:

• Vehicle stationary
• Engine stationary
• Brake pedal not operated
• Partial vacuum > -300 mbar
• Vacuum pump not activated