Installation Location
The suction-jet pump is located in the vacuum hose between the inlet pipe and the brake booster.
Scheme 11
Scheme 12
The suction-jet pump has 2 bypasses. The bypass with large cross-sectional area leads to a rapid vacuum build-up in the brake booster. The bypass with reduced cross-sectional area accelerates the air drawn in. This leads to a higher vacuum in the suction-jet pump. The vacuum to the brake booster is thus intensified. The suction-jet pump influences idling-speed control through its air requirement. For this reason, the suction-jet pump is activated or deactivated by a solenoid valve controlled by the DME.
The suction-jet pump is actuated in the following situations
- Coolant temperature below 70 °C
- Drive position engaged (automatic transmission)
- A/C compressor switched on