The remote function actuator (RFA) module performs the functions of interpreting the signals from the transmitter and controlling the requested vehicle function via class 2 serial data or by discreet input. The RFA module does not directly control any functions but is a interpreter for the transmitter to tell other modules what is requested. The RFA module is able to differentiate between the various transmitters and must be programmed to accept signals from all transmitters if one or both are to be replaced or spares are added.

The transmitter unit is a battery powered, water resistant, radio frequency signal generator. Each transmitter is uniquely recognized by the RFA module. The RFA module must be reprogrammed to accept a replacement transmitter.

The keyless entry system uses a system called rolling code. When the transmitter and the RFA module are initially programmed, a code is established that is unique to the transmitter and the RFA module. Each time the transmitter is used, within range of the vehicle, a new code is set. The transmitter sends the code to the RFA module, the module recognizes that it is from a programmed transmitter and it learns the new code.

When the transmitter goes out of synchronization with the RFA module you have to re-synchronize it, the module recognizes the transmitter as a programmed transmitter and establishes a new code sequence with the transmitter.