Walker Products Manifold absolute pressure sensors (MAP Sensor) measure manifold pressures through changing voltage and sends this information to the onboard computer. The computer uses this and other inputs to calculate the correct amount of fuel delivered. Symptoms of failure include poor starting, detonation, a check engine light, and or no start conditions. Sensors are non-serviceable and therefore must be replaced when non-functional. Walker Products began supplying the fuel system and engine management needs of the automotive industry since 1946. We continue our commitment to supplying products manufactured to meet or exceed OEM standards and specifications with the highest quality products. 2007-2016 BMW 1 Series M,BMW 135i,BMW 335i xDrive,BMW 335i,BMW 335is,BMW 335xi,BMW 535i GT,BMW 535i xDrive,BMW 535i,BMW 535xi,BMW 550i GT xDrive,BMW 550i GT,BMW 550i xDrive,BMW 550i,BMW 650i Gran Coupe,BMW 650i xDrive Gran Coupe,BMW 650i xDrive,BMW 650i,BMW 740i,BMW 740Li,BMW 750i xDrive,BMW 750i,BMW 750Li xDrive,BMW 750Li,BMW 760Li,BMW Alpina B7 xDrive,BMW Alpina B7,BMW Alpina B7L xDrive,BMW Alpina B7L,BMW X5,BMW X6,BMW Z4,