Keyless Entry System and Remote Functions: Overview Chevrolet Tahoe III

Circuit/System Description

When replacing a remote control door lock receiver (RCDLR), the service replacement part is shipped with no installed software. Before the new RCDLR is operational, a software calibration is required to be downloaded using the SPS terminal. Failure to download this software calibration will result in the setting of DTC B1008.

The remote control door lock receiver (RCDLR) monitors the number of keyless entry transmitters programmed. Until at least one transmitter is programmed, the RCDLR determines a malfunction condition exists.

With each press of a keyless entry transmitter button, a message containing the current battery state of the transmitter is sent to the remote control door lock receiver (RCDLR) along with the commanded keyless entry function.

The garage door opener (GDO) is a transmitter operating between 288 and 399 MHz. The GDO has three buttons that may be programmed for individual transmitter/receiver combinations to control up to three GDOs, security gates, lighting systems, etc. Each button represents a unique transmitter code section, which operates independently of the other buttons, and may be considered a separate transmitter.

The keyless entry system is a vehicle entry device. The keyless entry will unlock the vehicle doors or open the rear compartment when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the keyless entry transmitter sending a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via a message over the serial data line. A low transmitter battery or radio frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

Remote vehicle start (RVS) begins as an RF message received by the remote control door lock receiver (RCDLR) from a keyless entry transmitter. The RVS request is sent by the RCDLR to the body control module (BCM) via serial data. The BCM monitors system conditions such as content theft deterrent (CTD), hood ajar status, and body DTCs to determine if an RVS event will occur. If conditions are determined to be acceptable, the RVS message is sent to the engine control module (ECM). The ECM monitors system conditions such as engine control parameters and vehicle theft deterrent (VTD) to determine if engine starting will be allowed. If conditions are acceptable, the ECM will initiate engine starting. During the engine run time in a RVS attempt, before the operator enters the vehicle, the ECM may discontinue engine operation if system conditions require it or a message is received from the BCM requesting the engine be turned OFF.

Garage Door Opener Description and Operation

The garage door opener (GDO) is fixed and rolling code capable. Rolling code is a system that allows the code that the customers receiver receives from the GDO to change every time the GDO is used within operating range of the receiver. Rolling code programming requires the customer to push a learn/program button on the GDO receiver at their home. This button is usually located on the receiver unit under a cover (light cover) on one end of the unit. The customer must follow the GDO manufacturers instructions to program/learn the receiver to accept the Universal Home Remote System as an authorized opener for their unit. When the receiver and the GDO are initially programmed together, a code is established and a new code is created for every new transmission. The software in the receiver recognizes the GDO and accepts the new code.

The GDO is compatible with most, but not all types and brands of transmitters. If a problem should occur with a compatibility conflict with a transmitter, call 1-866-572-2728.

The GDO is a transmitter operating between 288-399 MHz. The power and range of the transmitter is limited to comply with laws governing the generation of radio frequency interference (RFI). The transmitter is programmed by the user to accept the signal generated by the user's transmitters.

The GDO has 3 buttons that may be programmed for individual transmitter/receiver combinations to control up to 3 GDOs, security gates, lighting systems, etc. Each button represents a transmitter code section of the transmitter, which operates separately from any other button, and may be considered a separate transmitter. Operation consists of simply pressing a button to activate the corresponding transmitter.

Keyless Entry System Description and Operation (Without Accessory 2 Way Remote)

The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the body control module (BCM) to remotely activate certain vehicle features. Keyless entry will lock/unlock the doors/liftgate, operate the power liftgate (if equipped), or release the liftglass when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via a serial data message to the BCM. A low transmitter or vehicle battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following components

1. Door locks
2. Liftgate lock
3. Power liftgate, if equipped
4. Liftglass, if equipped
5. Remote vehicle starting, if equipped
6. Illuminated entry lamps
7. Vehicle locator/Panic alarm

The keyless entry system has the following components

1. Keyless entry transmitters
2. Keyless entry antenna, if equipped
3. BCM
4. RCDLR

Unlock All Doors - Second Operation

Momentarily press the transmitter UNLOCK button a second time, within 5 seconds of the first press, to perform the following functions

1. Unlock the remaining doors.
2. Unlock the liftgate, if equipped.

Keyless Entry System Description and Operation (With Accessory 2 Way Remote)

The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the body control module (BCM) to remotely activate certain vehicle features. Keyless entry will lock/unlock the doors, or release the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via a serial data message to the BCM. A low transmitter or vehicle battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following components

1. Door locks
2. Liftgate lock
3. Power liftgate, if equipped
4. Liftglass, if equipped
5. Remote vehicle starting
6. Illuminated entry lamps
7. Vehicle locator/Panic alarm

The keyless entry system has the following components

1. Keyless entry transmitters
2. BCM
3. 2 Way Advance Remote Start RCDLR
4. 2 Way Advanced Remote Start Antenna

Momentarily press the transmitter UNLOCK button a second time, within 5 seconds of the first press, to perform the following functions

1. Unlock the remaining doors.
2. Unlock the liftgate, if equipped.
3. Indicate all doors are unlocked on the transmitter LCD-All LCD door segments will disappear