Voltmeter Gage

When your engine is not running, but the ignition is in RUN, this gage shows your battery’s state of charge in DC volts.
When the engine is running, the gage shows the condition of the charging system. The gage may transition from a higher to lower or a lower to higher reading, this is normal. Readings between the low and high warning zones indicate the normal operating range. The voltmeter gage may also read lower when in fuel economy mode.
This is normal.
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. 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 maximum power.
You can only drive for a short time with the reading in either warning zone. If you must drive, turn off all unnecessary accessories.
Readings in either warning zone indicate a possible problem in the electrical system. Have the vehicle serviced as soon as possible.
See also:
Cleaning the Mirror
Do not spray glass cleaner directly on the mirror. Use a soft towel dampened
with water. ...
Key and Lock Messages
NO REMOTE DETECTED
This message displays when the transmitter battery is weak on vehicles with keyless
access.
See “Starting the Vehicle with a Low Transmitter Battery” under Remote Keyless
...
Maintenance Replacement Parts
Replacement parts identified below by name, part number, or specification can
be obtained from your dealer.
Part
GM Part Number
ACDelco Part Number
Engine Air Cleaner/Filter
...
