Brake 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 brake control module (4/16) (called ABS module on model years up to and including 2001) informs the driver information module (5/1) via the Control area network (CAN) if there is a fault in the brake system. The driver information module indicates this to the driver by lighting the red general warning lamp and displaying a text message.
The brake fluid level sensor detects the level of the brake fluid in the reservoir. When the level is low, a switch in the sensor closes and the warning lamp lights. This function is directly connected to the driver information module.