The exhaust flex pipe can fail causing excessive exhaust noise from the front/center area of the vehicle. The flex pipe is a flexible joint in the exhaust that allows for engine movement.
Resources for the Repair and Maintenance of your 2009 Saab 9-5
2009 Saab 9-5
2009 Saab 9-5 Problems
If the HID head lights are flickering or have failed, it may be caused by the window washer fluid leaking onto the HID modules. The washer fluid check valve for the head light washers develops the leak and drips onto the modules mounted under the head light assemblies.
The head gasket may leak oil externally. The oil will be visible around the cylinder head and block area.
The rear shock absorbers can fail on the wagon models creating a bouncy ride from the rear of the vehicle.