@jansla thanks for the extra details on the MAP sensors. No you are not the only one who had the wrong sensor fitted in the factory, @Fredastaire reported this many moons ago. I think incorrect/ different differential DPF sensors were also fitted for a while as an alternative due to correct specified being unavailable (cynics might suggest a cost saving exercise).
I include this here as being aimed specificaly at P238 (The main discussion relates to a 2012 150 engine)
Extract from a german Ducato website
The error P0238 is a diagnosed electrical fault of the AD (Analog / Digital) converter in the ECU (Engine Control Unit):
Definition:
Turbocharger-Supercharger Boost Pressure Sensor Circuit High
Description:
The (K37) Boost Pressure Sensor Signal circuit voltage is above 4.9 volts for 2.0 seconds.
Cause:
5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE --> the 5 volt voltage generated in the ECU has a connection to the operating voltage
BOOST PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE--> the measuring line from the sensor to the ECU or in the ECU has a connection to the operating voltage
BOOST PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO THE 5-VOLT SUPPLY CIRCUIT-->the measuring line from the sensor to the ECU or in the ECU has a connection to the 5 volt voltage
SENSOR GROUND CIRCUIT OPEN/HIGH RESISTANCE --> Sensor ground connection open or high impedance
BOOST PRESSURE SENSOR-> Sensor defective
POWERTRAIN CONTROL MODULE (PCM) --> Powertrain control unit
I would make a data recording of the pressure and temperature value. If there is an electrical defect there is no continuous curve, but one with jumps and peaks and dips due to a loose contact in the wiring harness or moisture....
