Cadillac CTS-V 2009 Owner's Manual page 210

If moving the transmitter to different locations within
the vehicle does not help, place the transmitter in the
center console transmitter pocket with the buttons facing
the front of the vehicle and then start the vehicle.
•
The vehicle's battery voltage is low. The battery
voltage must be above 10 volts for the keyless
access transmitter to be detected properly.
3-62
Electronic Key Not Detected Restart
Allowed
If the vehicle has the keyless access system, this
message displays when the keyless access transmitter is
not detected inside the vehicle while you are trying to turn
the ignition off. The vehicle may be near a strong radio
antenna signal causing the keyless access system to be
jammed. If you have the keyless access transmitter with
you, get out of the vehicle and lock the doors. If you do
not have the keyless access transmitter with you, you will
be able to start the vehicle again within five minutes, or
until the vehicle's content theft deterrent system is armed.
See Starting the Engine on page 2-33 for more
information.
Engine Hot A/C (Air Conditioning) Off
This message displays when the engine coolant
becomes hotter than the normal operating temperature.
See Engine Coolant Temperature Gage on page 3-42.
To avoid added strain on a hot engine, the air
conditioning compressor automatically turns off. When
the coolant temperature returns to normal, the air
conditioning compressor turns back on. You can
continue to drive the vehicle.
If this message continues to appear, have the system
repaired by your dealer/retailer as soon as possible
to avoid damage to the engine.