2010 Buick LaCrosse Owner's Manual - Page 143

Lighting The battery can be discharged at idle if the electrical loads are very high. This is true for all vehicles. This is because the generator (alternator) may not be spinning fast enough at idle to produce all the power that is needed for very high electrical loads. A high electrical load occurs when several of the following are on, such as: headlamps, high beams, fog lamps, rear window defogger, climate control fan at high speed, heated seats, engine cooling fans, trailer loads, and loads plugged into accessory power outlets. EPM works to prevent excessive discharge of the battery. It does this by balancing the generator's output and the vehicle's electrical needs. It can increase engine idle speed to generate more power, whenever needed. It can temporarily reduce the power demands of some accessories. Normally, these actions occur in steps or levels, without being noticeable. In rare cases at the highest levels of corrective action, this action may be noticeable to the driver. If so, a Driver Information Center (DIC) message might be displayed, such as BATTERY SAVER ACTIVE, BATTERY VOLTAGE LOW, or LOW BATTERY. 5-7 If one of these messages displays, it is recommended that the driver reduce the electrical loads as much as possible. See Driver Information Center (DIC) on page 4‑25. Battery Power Protection The battery saver feature is designed to protect the vehicle's battery. If the exterior lamps or any interior light is left on and the ignition is turned off, the battery rundown protection system automatically turns the lamp off after about 10 minutes.