2004 Subaru Legacy Owner's Manual - Page 157

Instruments and controls The VDC warning light does not come on when the ignition switch is turned to the "ON" position. The VDC warning light remains on after the engine has started and stays lit even when the vehicle speed reaches about 8 mph (12 km/h). The VDC warning light comes on while the vehicle is running. If the electrical circuit of the VDC system itself becomes faulty, the VDC warning light only comes on. At this time, the ABS (Anti-lock Brake System) remains fully operational. The warning light comes on when the electronic control system of the ABS/VDC system becomes faulty. The VDC system provides its ABS control through the electrical circuit of the ABS system. Accordingly, if the ABS is inoperative, the VDC system also becomes unable to provide ABS control. As a result, the VDC system becomes inoperative, causing the VDC warning light to come on. Though both the VDC and ABS systems are inoperative in this case, the ordinary functions of the brake system are still available. You will be safe while driving with this condition, but you should have your vehicle checked at a SUBARU dealer as soon as possible. NOTE If the warning light behavior is as described below, the VDC system may be considered normal. The warning light comes on right after the engine is started but goes out immediately, remaining off. The warning light remains on after the engine has been started, but it goes out when the vehicle speed reaches 8 mph about (12 km/h). The warning light comes on during driving, but it goes out immediately and remains off. Brake system warning light (U.S.) (Canada) Driving with the brake system warning light on is dangerous. This indicates your brake system may not be working properly. If the light remains on, have the brakes inspected by a SUBARU dealer immediately. If at all in doubt about whether the brakes are operating properly, do not drive the vehicle. Have your vehicle towed to the nearest SUBARU dealer for repair. 3-14