alternator PONTIAC GRAND PRIX 2008 Owners Manual

Electric Power Management
The vehicle has Electric Power Management (EPM) that
estimates the battery’s temperature and state of charge.
It 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 gage
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. If so, a Driver Information Center (DIC)
message might be displayed, such as Battery Saver
Active. If this message is displayed, it is recommended
that the driver reduce the electrical loads as much
as possible. SeeDIC Warnings and Messages
on page 3-67.
Battery Run-Down Protection
The vehicle has a feature to help prevent the battery
from draining in case the interior, trunk, or underhood
lamps are accidentally left on. If any of these lamps are
left on while the ignition is in LOCK/OFF, they will
automatically turn off after 10 minutes. The lamps will not
come back on again until any of the following are done:
The ignition is turned to ON/RUN or
ACC/ACCESSORY.
The interior lamps control is turned completely to
the right, then back slightly to the left.
Open, or close and reopen, a door that is closed.
If the vehicle has less than 15 miles (25 km) on the
odometer, the battery saver will turn off the lamps
after only three minutes.
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