Volvo All Engines (2010 Emissions) Fault Code: SPN 108 FMI 4 PID: Barometric Pressure

The Ambient Pressure Sensor is located inside the Engine Control Module (ECM) and can therefore not be checked.
The signal is used to calculate intake manifold pressure (IMP) as well as to compensate for fuel when driving at high altitudes.
The engine control module (ECM) will set a diagnostic trouble code (DTC) if the sensor signal is not within predetermined limits, or the signal is not rational.

Conditions for diagnostic trouble code (DTC):
1) The barometric pressure (BARO) from the sensor is irrational

Observable symptoms
1) Poor response at high altitudes

Probable cause
1) Barometric Pressure (BARO) Sensor

Detailed information
1) The sensor is located in the engine control module (ECM) and therefore cannot be checked
2) The signal is used to calculate intake manifold pressure (IMP) as well as to control fuel compensation when driving at high altitudes
3) If the sensor is blocked by e.g. dirt, paint or stickers it may send an incorrect value