2009 Chevrolet Suburban Owner's Manual - Page 228
2009 Chevrolet Suburban Manual
Page 228 highlights
Readings in the low warning zone may occur when a large number of electrical accessories are operating in the vehicle and the engine is left at an idle for an extended period. This condition is normal since the charging system is not able to provide full power at engine idle. As engine speeds are increased, this condition should correct itself as higher engine speeds allow the charging system to create full power. If there is a problem with the battery charging system, this light will come on or the SERVICE BATTERY CHARGING SYSTEM DIC message will display. See DIC Warnings and Messages on page 3-64 and Charging System Light on page 3-39 for more information. The vehicle's hydraulic brake system is divided into two parts. If one part is not working, the other part can still work and stop the vehicle. For good braking, both parts need to be working well. If the warning light comes on and a chime sounds there could be a brake problem. Have the brake system inspected right away. This light can also come on due to low brake fluid. See Brakes on page 5-40 for more information. Brake System Warning Light With the ignition on, the brake system warning light comes on when the parking brake is set. If the vehicle is driven with the parking brake engaged, a chime sounds when the vehicle speed is greater than 5 mph (8 km/h). United States Canada This light comes on briefly when the ignition key is turned to ON/RUN. If it does not come on then, have it fixed so it is ready to warn if there is a problem. 3-40