General Warning Lamp
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2009 Volvo S60, 2008 Volvo S60, 2007 Volvo S60, 2006 Volvo S60, and 2005 Volvo S60. However, it is still accessible from the selected car via links, so may be relevant.
The function is to display different "faults" in the car. When a lamp lights this is followed by a text message which presents the driver with additional information about why the lamp has lit. From model year 2002 inclusive the color of the lamp has changed from orange to yellow / red. The lamp lights red in the event of serious faults, or yellow for less serious faults.