Differenzierte Sauganlage - and because German's can't pronounce this either, BMW just took the first two letters from each word and called this the DISA Valve.BMW's engineers discovered that the air path through the engine system has an impact on performance. In an effort to improve performance, BMW released the DISA valve in 1995. The valve is responsible for controlling … [Read more...] about Diagnosing a Failing BMW DISA Valve – Sypmtoms, Problems & Repairs