Keyless Entry: Description and Operation

KEYLESS ENTRY SYSTEM DESCRIPTION AND OPERATION

The keyless entry system is a supplementary vehicle entry device. Radio frequency interference or discharged batteries may disable the system.

Keyless entry allows you to operate the following components:
- The door locks
- The rear compartment lid release-Press and hold rear release button for greater than 1.5 seconds to activate.
- The illuminated entry lamps
- The panic alarm, instant alarm
- Remote start-Press and hold remote start button for greater than 1.5 seconds to activate a remote start.

The keyless entry system has the following main components:
- The transmitters
- The body control module (BCM)
- The remote control door lock receiver (RCDLR)-When you press a button on the transmitter, the transmitter sends a signal to the RCDLR. The RCDLR receives the signal and sends a class 2 serial data message requesting the appropriate function from the BCM.
- The hood ajar switch

Unlock Driver Door Only
Momentarily press the UNLOCK button in order to perform the following functions:
- Unlock the driver door only.
- Illuminate the interior lamps for approximately 10 seconds or until the ignition is turned ON.
- Flash the park lamps twice if the ignition is turned OFF and the doors are closed.
- Identify the driver to the radio-The radio will then revert to the station presets, the last station, the last volume settings, and the last playback mode used by that driver.

Unlock All Doors - Second Operation
Momentarily press the UNLOCK button a second time, within 5 seconds of the first press, in order to perform the following functions:
- Unlock all of the doors.
- Illuminate the interior lamps for approximately 10 seconds or until the ignition is turned ON.

Lock All Doors
Press the LOCK button in order to perform the following functions:
- Lock all of the doors.
- Immediately turn OFF the interior lamps.
- Flash the park lamps twice if the ignition is OFF and the doors are closed.
- Chirp the horn if the ignition is OFF and the doors are closed.

Remote Vehicle Start
The Remote Vehicle Start function allows the customer to start the vehicle while not in the car. It also allows starting up the vehicle heating or air conditioning system and other vehicle systems to provide the customer with a comfortable vehicle when they enter it. The distance the customer can be away from the vehicle and operate this feature has a design requirement of 60 meters. The Remote Vehicle Start feature is started by the customer pressing the lock and then the remote vehicle start (RVS) buttons on their key fob. The turn signal lamps will flash if this feedback is enabled on to indicate the vehicle has received the Remote Start Request. Each time the customer does a remote vehicle start, the vehicle doors are locked, however they may then be unlocked/locked with the key fob or key at anytime. Once the vehicle has been started, there is visible feedback, if the feedback is enabled on, to the customer via a turning ON of non-white exterior lights. There are vehicle conditions which will prevent a remote start, for example if the hood is not closed or the key is in the ignition. The Remote Vehicle Start feature once activated is allowed to run for 10 minutes. At any time during this 10 minute time the 10 minute time-out can be reset once. This feature is called a Remote Vehicle Start Continue. This allows a maximum of 20 minutes of engine running via the Remote Vehicle Start feature without a reset. If the Remote Vehicle Start Continue is done at 7 minutes into the initial 10 minute time-out, a total of 17 minutes of engine running would occur. A remote vehicle start, once active, can be stopped by pressing a dedicated RVS button on the key fob or by pressing the Vehicle Hazard switch located inside the vehicle. It can also be stopped by entering the vehicle and inserting the ignition key and leaving the ignition OFF, and then returning to the ignition OFF position, in a standard ignition switch system, or by pushing the Easy Key mode switch OFF button in an Easy Key System. If equipped and supported, a remote vehicle start may also be stopped by the GM OnStar system. Remote vehicle start is active and an attempt is made to shift the vehicle into gear without satisfying the vehicle theft system requirements, the engine will be shut OFF. Remote start will also be stopped if any DTCs that turn ON the SES/MIL are stored in history or current status.

Customer Programming Method for Enabling/Disabling the RVS Feature
1. Turn ignition ON, SYSTEM POWER MODE = ACC or RUN.
2. ALL DOORS MUST BE CLOSED, DRIVER DOOR INPUT and PASSENGER DOORS INPUT = Closed.
3. To DISABLE press and hold the driver power door unlock switch until you get a single chime.
4. While still pressing the driver power door unlock switch, press the remote vehicle start (RVS) button on the key fob, then you will get 3 chimes indicating a successful DISABLE.
5. The body control module (BCM) sets the RVS Enable to FALSE.
6. This procedure will result in the doors being UNLOCKED.
1. To ENABLE press and hold the driver power door lock switch until you get a single chime.
2. While still pressing the driver power door lock switch, press the RVS button on the key fob, then you will get 3 chimes indicating a successful ENABLE.
3. The BCM sets the RVS Enable to TRUE.
4. This procedure will result in the doors being LOCKED.

On vehicles with a driver information center (DIC), the RVS feature can be DISABLED and ENABLED just like other items programmable via the DIC.

Vehicles with a valet switch may provide Enabling/Disabling of the RVS. This function is also programmable through the DIC.

Remote Vehicle Start Features That Allow A Remote Vehicle START/CONTINUE
- The remote vehicle start (RVS) feature must be enabled.
- A remote vehicle start request command is received by the body control module (BCM).
- The hood ajar switch status is closed.
- The number of remote start attempts is less than 3.
- The key is not in the ignition, or for vehicles with easy key fob, is not inside the vehicle and the power mode is OFF.
- The content theft deterrent (CTD) alarm has not been violated since last CTD arming.
- The remote start voltages are within proper operating ranges 6-16 volts.
- There are no DTCs or serial data communication failures with RVS related systems.
- The transmission status is Park/Neutral and the vehicle speed is zero.

Conditions to Stop A Remote Vehicle Start
- Hood ajar switch status is - OPEN.
- Inserting the key in the ignition and turning the key to any non-off power modes, and returning the key to the OFF position
- On vehicles equipped with easy key, pressing the mode switch OFF button
- The remote vehicle start (RVS) time has elapsed or timed out.
- The RVS master receives a run abort message from the powertrain control module (PCM).
- Hazard shutoff switch status is - ACTIVE.
- By GM OnStar system, if equipped
- By content theft deterrent (CTD) system, if equipped, and alarm status becomes Violated
- RVS system voltage out of range, under 6 volts or over 16 volts
- System back up or power moding becomes Enabled.
- DTCs set for any related systems, or serial data communication failure for any modules that support the RVS function

If the RVS master stops a remote vehicle start for any of these conditions, further remote vehicle starting is not allowed until a RVS RESET has occurred.

A RVS RESET occurs when, in an ignition switch vehicle, the key is inserted and rotated into the Run position, power mode of RUN is seen, and PCM Vehicle Theft Fuel Continue is received over serial data.

In an easy key vehicle, the key fob is present in the vehicle, the brake pedal is pressed and held, and the Start button is pushed and PCM VEHICLE THEFT FUEL CONTINUE message is received over serial data.

This action results in resetting the RVS counters to MAX starts allowed and the RVS Attempts to 0.

Rolling Code
The keyless entry system uses rolling code technology. Rolling code technology prevents anyone from recording the message sent from the transmitter and using the message in order to gain entry to the vehicle. The term rolling code refers to the way that the keyless entry system sends and receives the signals. The transmitter sends the signal in a different order each time. The transmitter and the body control module (BCM) or the remote control door lock receiver (RCDLR) are synchronized to the appropriate order. If a programmed transmitter sends a signal that is not in the order that the BCM or the RCDLR expects, the system will not function. This occurs after 256 presses of any button on the transmitter when it is out of range of the vehicle.