GM Service Manual Online
For 1990-2009 cars only

Remote Function Actuation (RFA) System

The Remote Function Actuation (RFA) system performs the following functions:

    • Transmitter remote control of various vehicle systems without physical contact of any switches on the vehicle
    • Tire Pressure Monitoring (TPM) system functions

Refer to Tire Pressure Monitor System .

The RFA system consists of the following components:

    • A transmitter located on the operator's key fob
    • A receiver
    • An integral antenna

The RFA system does not directly control its functions. but relies on one of the following systems in order to perform the driver commands:

    • The Body Control Module (BCM) -- in order to provide Universal Theft Deterrent (UTD), hatch release, horn, and vehicle lamp control
    • The Door Control Module (DCM) -- in order to provide all door lock functions
    • The Instrument Panel Cluster (IPC) -- in order to provide RFA system programming and vehicle personalization functions.

When the RFA receives a command from the transmitter, a message is sent via the serial data line to the system module capable of performing the needed function.

The RFA system is intended to be used as a supplementary to the vehicles conventionally operated lock/unlock system. It is not intended to replace, but should be used in conjunction with the door lock key. The system could disable due to radio frequency interference or a low transmitter battery. Therefore, always maintain vehicle access with a door key

RFA System Functions

The passive RFA system consists of the following major components:

    • A receiver with integrated antenna
    • A low power signal transmitter

The remote control receiver is located over the LH rear wheelhouse. The receiver is capable of recognizing three transmitter codes. The receiver receives and transmits various information from many systems in order to perform specific functions. The RFA system uses the same receiver as the TPM system. Refer to Tire Pressure Monitor System in Tire Pressure Monitor.

The RFA system allows the user to passively lock or unlock the vehicle through a transmitter located on the user's key chain. The RFA transmitter is a battery powered, water resistant, radio frequency signal generator. Replacement transmitters are available. After replacement, the remote control receiver and the transmitter must be programmed to accept the new transmitter.

The RFA transmitter consists of four manual buttons and a passive slider switch. The operation of the manual and passive features is described below:

Manual Features

    • Door UNLOCK Button -- programmed transmitter in range/key out of ignition
    • Door LOCK Button -- programmed transmitter in range/key out of ignition
    • HATCH Button -- programmed transmitter in range/button pressed
    • PANIC Button -- programmed transmitter in range/button pressed

When the transmitter manual UNLOCK button is pressed once, the transmitter sends an identification code to the receiver to unlock the driver door. The receiver sends the message to the driver DCM on the serial data line to unlock the driver door. The DCM will then unlock the driver door. The BCM then disarms the UTD system. The BCM will also activate the courtesy lamps if the ambient light is low. If the UNLOCK button is pressed again within 10 seconds, the receiver sends a second message to the passenger DCM to unlock the passenger door. The DCM then unlocks the passenger door.

When the transmitter manual LOCK button is pressed, the transmitter sends an identification code to the receiver to lock both doors. The receiver sends the message to both of the DCMs on the serial data line to lock both doors. Both DCM will then lock both doors. The BCM then arms the UTD system.

When the manual HATCH button is pressed, the transmitter sends an identification code to the receiver to release the hatch. The receiver sends the message through the serial data line to the BCM. The BCM then disarms the UTD system and activates the hatch release relay, and the hatch opens.

When the manual PANIC button is pressed, the transmitter sends an identification code to the receiver to activate the panic mode. The receiver sends the message through the serial data line to the BCM. The BCM activates the horn relay or flashes the lamps (depending on selected personalized options) for 90 seconds or until the panic button is pressed again.

Passive Features

    • Unlocking -- programmed transmitter in range/key out of ignition
    • Locking -- all programmed transmitters out of range for 5 seconds
    • PASSIVE ON/OFF Switch

With the passive unlocking feature, the motion sensor in the transmitter causes the transmitter to send an identification code to the receiver. The receiver will unlock the driver door or both doors depending on selected features. Refer to Remote Keyless Entry The receiver sends the message on the serial data line to the DCMs to unlock the appropriate doors. The BCM then disarms the UTD system and activates the courtesy lamps if ambient light is low. The appropriate doors will then unlock. Inserting the ignition key disables the passive unlocking feature.

With the passive locking feature, the receiver sends a message through the serial data line to the DCMs to lock both doors, and the doors lock. The BCM then arms the UTD system. Inserting the ignition key disables the passive locking feature.

The PASSIVE ON/OFF slider switch provides the capability to deactivate the passive unlocking and locking features. Sliding the switch to OFF turns off the transmitter motion sensor which deactivates the passive functions. Sliding the switch to ON turns on the sensor which activates the passive functions. The manual button functions are not affected whether the slider switch is in the PASSIVE ON position or the PASSIVE OFF position.

Personalization

The user of the RFA system, will be able to choose from the following personalized options:

    • Whether or not the passenger door unlocks passively with the driver door.
    • Approach lights illuminate with unlock command (passive or manual).

System personalization can only be accessed through the DIC by performing the following procedure:

  1. Press the RESET button in order to clear any IPC warnings.
  2. Press the OPTIONS button on the DIC until the IPC displays PASSIVE UNLK.
  3. Using the RESET button, select PASSIVE UNLK DRIVER or PASSIVE UNLK BOTH.
  4. Press the OPTIONS button on the DIC until APPROACH LIGHTS is displayed.
  5. Using the RESET button, select ON or OFF.

Arming/Disarming Universal Theft Deterrent (UTD)

When the RFA system sends a lock command to the DCMs, the BCM will arm the UTD system. The BCM then turns off the courtesy lamps and sound the horn, indicating that the UTD is armed. Whenever the doors are unlocked or the hatch is release, the BCM disarms the UTD.

To send a disarm UTD message to the BCM, the RFA system must see the following conditions:

    • A valid transmitter is in range.
    • The key is not in the ignition.
    • The receiver has identified the passive or manual unlock command or the hatch release command from a valid transmitter.

To send an arm UTD message to the BCM, the RFA system must see the following conditions:

    • All valid transmitters are out of range for 5 seconds (passive mode activated) or the transmitter LOCK button has been pressed.
    • The key is not in the ignition.

RFA Operational Range

Operational range varies with the orientation of the transmitter. For best performance, hold the transmitter vertically, with the buttons facing you and the bottom cover of the transmitter towards the vehicle. The operational range of the transmitter in the passive mode is considerably less than it is in the manual activation mode. As battery life decreases, so does the maximum operational range of the RFA transmitter. In most cases, the transmitter battery should only be replaced when the operational range has severely decreased.


Object Number: 65707  Size: MH

Mode

Range

Transmitter Location

Manual

15.2-30.4 m

(50-100 ft)

A, B, C

Passive

1.5-7.2 m

(5-25 ft)

A, B, C