Cadillac CTS Owner's Manual page 326

The battery is in the trunk, behind
the trim panel, on the passenger
side of the vehicle. Refer to the
replacement number shown on the
original battery label when a new
battery is needed.
Battery posts, terminals, and
related accessories contain lead
and lead compounds, chemicals
known to the State of California to
cause cancer and reproductive
harm. Wash hands after handling.
After a power loss, such as
disconnecting the battery or
removing the maxi fuses in the
power distribution fuse block, the
following steps must be performed
to calibrate the electronic throttle
control. If this is not done, the
engine will not run properly.
1. Turn the ignition on but do not
start the engine.
2. Leave the ignition on for at least
three minutes so that the
electronic throttle control will
cycle and relearn its home
position.
3. Turn the ignition off.
4. Start and run the engine for at
least 30 seconds.
Batteries have acid that can burn
you and gas that can explode.
You can be badly hurt if you are
not careful. See
for tips on working
around a battery without
getting hurt.
Infrequent Usage: Remove the
black, negative ( ) cable from the
battery to keep the battery from
running down.