The UP28 vacuum pump is activated on demand to support the evacuation of the brake booster. The UP28 can provide the necessary vacuum for the brake booster in a wide range of situations when the internal combustion engine is unable to do so, e.g. during the cold start/warm-up phase, at high altitudes or when using the air-conditioning system. The UP28 is installed parallel to the main combustion engine and evacuates filtered air via the brake booster and flexible pneumatic hoses.
Electrical contact between the UP28 and the ECU is made using a cable equipped with an engine compartment connector and attached to the vacuum pump.
Over 17 million electric vacuum pumps have been produced since 1999.