Ford 2009 Flex Owner's Manual page 342

Maintenance and Specifications
If you see any corrosion on the battery or terminals, remove the cables
from the terminals and clean with a wire brush. You can neutralize the
acid with a solution of baking soda and water.
It is recommended that the negative battery cable terminal be
disconnected from the battery if you plan to store your vehicle for an
extended period of time. This will minimize the discharge of your battery
during storage.
Note: Electrical or electronic accessories or components added to
the vehicle by the dealer or the owner may adversely affect
battery performance and durability.
WARNING: Batteries normally produce explosive gases which
can cause personal injury. Therefore, do not allow flames, sparks
or lighted substances to come near the battery. When working near the
battery, always shield your face and protect your eyes. Always provide
proper ventilation.
WARNING: When lifting a plastic-cased battery, excessive
pressure on the end walls could cause acid to flow through the
vent caps, resulting in personal injury and/or damage to the vehicle or
battery. Lift the battery with a battery carrier or with your hands on
opposite corners.
WARNING: Keep batteries out of reach of children. Batteries
contain sulfuric acid. Avoid contact with skin, eyes or clothing.
Shield your eyes when working near the battery to protect against
possible splashing of acid solution. In case of acid contact with skin or
eyes, flush immediately with water for a minimum of 15 minutes and
get prompt medical attention. If acid is swallowed, call a physician
immediately.
WARNING: Battery posts, terminals and related accessories
contain lead and lead compounds. Wash hands after handling.
Because your vehicle's engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. To begin this process:
342
2009 Flex (471)
Owners Guide, 2nd Printing
USA (fus)