When the engine is not running, but the ignition is on, this gage shows the battery's state of charge in DC volts.
When the engine is running, this gage shows the condition of the charging system. The vehicle's charging system regulates voltage based on the state of charge of the battery. The voltmeter may fluctuate. This is normal. Readings between the low and high warning zones indicate the normal operating range.
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 idling for an extended period.
If there is a problem with the battery charging system, a SERVICE BATTERY CHARGING SYSTEM message appears in the Driver Information Center (DIC) and/or the charging system light comes on. See DIC Warnings and Messages and Charging System Light for more information.
However, readings in either warning zone can indicate a possible problem in the electrical system. Have the vehicle serviced as soon as possible.