Unfortunately, we don't have the 2.5 diesel engine in the US. The P012B code can be triggered by the following:
-Faulty Turbocharger/Supercharger Inlet Pressure Sensor
-Turbocharger/Supercharger Inlet Pressure Sensor harness is open or shorted
-Turbocharger/Supercharger Inlet Pressure Sensor circuit poor electrical connection
Read more:
P012B Turbocharger/Supercharger Inlet Pressure Sensor Circuit Range/Performance Downstream Of Throttle Valve
I would believe that it could cause you to go into limp mode. I did find that there are several YouTube videos that have diagnostic information pertaining to this code for this application, so that would be a good place to start. You should check the harness connections in the circuit to make sure the pins are clean, straight and not pushed out of the connector. Ideally, a factory service manual should be accessed where you can find the step-by-step diagnostics for that particular code along with the wiring diagrams, but I don't know of any places to access FSM's for vehicles outside of the US.