hi

I have this old but good condition MBW 5 series e39. it has the traction MIL on and fault code 75 for engine control module, engine speed. In the engine ecu I have, but the engine MIL is not on

53 crankshaft sensor incorrect signal
f4 crankshaft sensor segment error
7b activation map cooling
08 mass air flow sensor

I cleared codes but 53 and f4 returned on starting. here's hoping someone has had this problem before and cured the fault but does anyone have a pattern of a good crank sensor. does ecu have problems with water ingress etc

Ray