The B14 Factory Service Manual has a procedure for checking the MAP/BARO solenoid valve when P1105 is tripped. It is rather complex, and you will need a volt meter, but...
1- Warm up the car and pull the vacuum hose connected to the MAP/BARO switch solenoid with the engine idling. There should be vacuum there (~ -20in Hg). If NG, replace the hose.
2- Check the vacuum hose between the Absolute Pressure Sensor and the solenoid for splits/cracks and clogging (blow through it).
3- With the engine off, disconnect the solenoid electrical connector. Turn the ignition switch on. Check the voltage between terminal 2 (brown wire) and ground. It should be 12v (battery voltage). If no voltage, check the 10a fuse #21.
4- Check Absolute Pressure Sensor. Remove the sensor with its wiring connected. (Located near the top of the firewall next to the cruise control actuator [disk-shaped on a bracket]). Remove the hose and turn the ignition on. Voltage between terminal #2 (white wire) and ground should be 3.2-4.8v. Apply a vacuum to the hose and the voltage should be 1-1.4v lower than the first reading. If NG, the sensor is bad.
5- Check the solenoid. Remove the solenoid electrical connector and hoses and check the air passage continuity by applying 12v to the connections. With 12v on, there should be continuity between the two close hose connections, and no connection between the lone connector and the double connection closest to it. With no voltage applied it should be the opposite (no continuity between the close ones, and continuity between the far one and the closest double one). If NG the solenoid is bad.
I hope this is understandable.