VOLKSWAGEN issued a recall on the Q7 model

On certain vehicles equipped with a 3.0L TDI engine, a contaminated check valve may allow engine oil to enter the brake booster. Over time, this could degrade the brake booster diaphragm and cause it to rupture, affecting power assist brake performance and potentially causing a complete loss of power assist, resulting in increased brake pedal effort. An unexpected increase in pedal effort could increase the risk of a crash causing property damage and/or personal injury the risk of a crash. Correction: Dealers will inspect the brake booster system for oil contamination and replace a vacuum line, as necessary.