System Test of Vacuum System MSS65

System Test Of Vacuum System MSS65

This system test checks the leak-tightness of the vacuum system as well as the hose line to the idle actuators of cylinder bank 2.

First of all, the system test evaluates the sensor vacuum in relation to the model vacuum. When both vacuum levels have a certain relation, the system test of the engine is switched off.

After an engine-off period of 5 s, the first sensor measured value is determined; the second after 35 s engine-off period. This results in a leak-tightness test time of 30 s. If the system loses less than 5 mbar partial vacuum in this period, the system is regarded as tight.

The run conditions for the system test are:
- Vehicle stationary
- Engine at idle speed
- Catalytic converter heating not active
- Brake pedal not operated
- Electrical vacuum pump not activated