Hi, just new to the forum. Iv only used here for information and found it great, feel it only fair to share my experience.
Had MAF sensor fault on my e350 cdi 2010.
Got quoted £523+vat for whole monifold as the sensors come internal on my model.
Removed the air intake monifold and sprayed with CRC cleaner as recommended in an earlier post.
Plenty of oil and crap flushed out of the monifold. Also cleaned the MAP sensor as it was easy.
Reset all sensor parmeters, Car run for 100miles or so with no faults before light came back on however after another 50 mile or so faults cleared them selves and problem solved!
Thanks for advise and guidance.
Seems these sensors are tempermental, try reseting a few times before replacing part is my advice.