Battery Power Protection; Exterior Lighting Battery Saver - GMC Chevrolet Express 2022 Owner's Manual

When the battery's state of charge is low,
the voltage is raised slightly to quickly bring
the charge back up. When the state of
charge is high, the voltage is lowered
slightly to prevent overcharging. If the
vehicle has a voltmeter gauge or a voltage
display on the Driver Information Center
(DIC), you may see the voltage move up or
down. This is normal. If there is a problem,
an alert will be displayed.
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
SERVICE BATTERY CHARGING SYSTEM. If this
messages displays, it is recommended that
the driver reduce the electrical loads as
much as possible.

Battery Power Protection

This feature helps prevent the battery from
being drained, if the interior courtesy lamps
or reading lamps are accidentally left on.
If any of these lamps are left on, they
automatically turn off after 10 minutes,
if the ignition is off. The lamps will not
come back on again until one of the
following occurs:
The ignition is turned on.
The doors are closed and then re-opened.
Lighting

Exterior Lighting Battery Saver

The exterior lamps turn off about 10 minutes
after the ignition is turned off, if the parking
lamps or headlamps have been manually
left on. This protects against draining the
battery. To restart the 10-minute timer, turn
the exterior lamp control to the
and then back to the or
To keep the lamps on for more than
10 minutes, the ignition must be on or in
ACC/ACCESSORY.
95
position
position.