A method and system for cleaning a brake booster aspirator shut-off valve are provided. The shut-off valve is operable to selectively permit flow of intake air through an aspirator; the aspirator bypasses a throttle of an engine and provides a vacuum source for a brake booster. The method comprises determining whether the shut-off valve may require cleaning, opening the shut-off valve so as to permit a flow of air through the shut-off valve and clean the shut-off valve and adjusting the throttle position of the engine to compensate for the additional flow of intake air through the aspirator.