See also:

Extreme Cold Weather (Below –20°F Or –29°C)
To ensure reliable starting at these temperatures, use of an externally-powered electric engine block heater (available from your authorized dealer) is recommended. ...

Programming Additional Transmitters
Refer to Sentry Key “Customer Key Programming.” If you do not have a programmed RKE transmitter, contact your authorized dealer for details. ...

Before You Begin Programming HomeLink
Be sure that your vehicle is parked outside of the garage before you begin programming. For more efficient programming and accurate transmission of the radio-frequency signal it is recommended th ...