Electric Power Management
This vehicle has Electric Power Management (EPM),
an advanced control system. It estimates the battery's
temperature and state of charge and then adjusts the
voltage for best performance and extended life of the
battery.
When the battery's state of charge is low, the voltage is
raised slightly to quickly put the charge back in. When
the state of charge is high, the voltage is lowered
slightly to prevent overcharging. If the vehicle has a
voltmeter gauge or 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 loads are on: 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.
Battery Run-Down Protection
The vehicle has a battery saver feature designed to
protect the vehicle's battery.
When any interior lamp is left on and the ignition is
turned off, the battery rundown protection system
automatically turns the lamp off after 20 minutes.
This prevents draining of the battery.
4-15
