please can some one help, I have a 2003 ducato 2.8
I do no have 5 to battery voltage to the crankshaft sensor only 2.5v
Checked the fuses in the engine bay
The elearn from fiat posted by @Communicator is correct.
The rev counter can be an indication of crank sensor failure depending on how the rev counter functions but is not infallible. I do not know why rev counter not functioning.
You could measure ac volts between the crank sensor signal wires at the ecu connector engine cranking to check your new sensor.
You could see if your old crank sensor is magnetic if you still have it.
With ecu plug disconnect . Check the resistance between the connectors in plug for the crank sensor, the resistance should be the same as a new crank sensor. If open circuit the there is a break in the crank sensor circuit.
The crank sensor provides a voltage signal to the ecu . The sensor is "dumb" and does not require any power or voltage from the ecu. So you would not expect a particular voltage at the ecu side of crank sensor wiring.
The only way you would know if the voltage you are reading for the crank wires at the ecu is normal or not is test an identical working ecu.
Test the resistance of the crank sensor at disconnected ecu plug .
