This information was taken from a working 2017 Ducato. Parts of it maybe applicable to other models and general MAP sensors.
It is at front of engine on the inlet manifold
MAP-sensor under here.jpg
Map sensor Multiecuscan Data
MAP Sensor Pressure Calibration Engine A.jpg

MAP sensor Air temperature Calibration Engine A.jpg

This Gives sufficient info to compare with your results. Typicaly errors will be reported if signal voltages are bellow 0.5V or above 4.5V. This may be as a result of signal shorting to ground or +5V reference.
A 4-wire manifold absolute pressure sensor has a 5-volt reference voltage, an earth connection and 2 signal wires
The pressure and the intake air temperature sensor IAT.

Map sensor Removal.
1 Undo and remove the hose clip on the throttle body, suitably squash the intercooler hose to displace it to your left (van rhs).
2 Use a mirror and torch to find the three fixing screws for the throttle body (1long at bottom two shorter at top. Now undo them, they are hex socket caphead setscrews, 5mm Allen key, you need an insert type with a 1/4 drive long extension.
Screws positioned at 2,6,10 oclock.

With screws removed you just move the throttle body out of the way STILL CONNECTED.
3 Now with torch locate the single fixing screw of the MAP, a small torx screw. Remove the screw and lift the sensor upwards out of it's hole.


Only now disconnect it's wiring plug.