Enable criteria:

WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

General condition for this diagnostic trouble code: Atmospheric pressure must exceed 72 kPa as well as coolant and intake air temperature must exceed -7°C.
Test 1: Crankshaft stationary, even after ignition OFF. Car stationary. The difference in pressure between the other two absolute pressure sensors in the system less than 10 kPa.
Test 2: Engine running. Engine speed above 1300 RPM. Engine load lower than 110 mg/c. Accelerator pedal fully released.