For 1990-2009 cars

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

• | The illuminated entry lamps

• | The panic alarm (instant alarm)

The keyless entry system has the following main components:

• | The transmitters

• | The Body Control Module (BCM)

• | The Remote Door Lock Reciever (RCDLR) which was added midyear to certain vehicles.

When you press a button on a transmitter, on vehicles with ONLY a BCM, the BCM recieves and interprets the signal and activates the requested function. On vehicles with a RCDLR, the transmitter sends a signal to the RCDLR. The RCDLR recieves the signal and sends a serial data message requesting the appropriate function from the BCM.

### Unlock Driver's 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 parklamps 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 parklamps twice if the ignition is OFF and the doors are closed.

• | Chirp the horn if the ignition is OFF and the doors are closed (if turned ON in personalization).

### Rear Compartment Lid Release

A single press of the rear compartment release button will open the rear compartment lid under any of the following conditions:

• | The ignition is turned OFF.

• | The park brake is engaged.

• | The vehicle speed is less than 2 mph (3 kph).

The interior lamps will not illuminate.

### Alarm

A single press of the panic button or an OnStar request performs the following functions:

• | Illuminates the interior lamps.

• | Pulses the horn.

• | Flashes the headlamps and the parklamps for 2 minutes or until one of the following conditions occurs:

- | The panic button is pressed again.

- | The ignition switch is turned to the RUN position with a valid key.

- | An OnStar request to deactivate the panic function is received.

### 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 Reciever 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.

### Automatic Synchronization

The keyless entry transmitters do not require a manual synchronization procedure. If needed, the transmitters automatically resynchronize when any button on the transmitter is pressed within range of the vehicle. The transmitter will operate normally after the automatic synchronization.