Keyless Entry System: Diagnosis Chevrolet Silverado 2500

Diagnostic Starting Point - Keyless Entry

Begin the system diagnosis with Diagnostic System Check - Remote Keyless Entry . The Keyless Entry Diagnostic System Check will provide the following information

1. The identification of the control module(s) which command the system
2. The ability of the control module(s) to communicate through the serial data circuit
3. The identification of any stored diagnostic trouble codes (DTCs) and their status

The use of the Diagnostic System Check will identify the correct for diagnosing the system and where the procedure is located.

Scan Tool Data List

The keyless Entry Scan Tool Data list contains all of the keyless entry related parameters that are available on the scan tool. The parameters in the list are arranged in alphabetical order. The column, "Data List," indicates the location of the parameter within the scan tool menu elections. Use the Keyless Entry Scan Tool Data List as directed by a diagnostic table or in order to supplement the diagnostic procedures. Begin all of the diagnostic procedures with Diagnostic System Check - Remote Keyless Entry .

Use the Scan Tool Data List only after the following is determined

1. There is no published DTC procedure nor published symptom procedure for the customer concern.
2. The DTC or symptom diagnostic procedure indicated by the diagnostic system check does not resolve the customer concern.

The Typical Data Values are obtained from a properly operating vehicle under the conditions specified in the first row of the Scan Tool Data List table.

Comparison of the parameter values from the suspect vehicle with the Typical Data Values may reveal the source of the customer concern.

Scheme 6

Scan Tool Data Definitions

RFA Serial Data Link: The scan tool displays Active/Inactive. The state of the keyless entry serial data circuit as commanded by the body control module (BCM).

Scheme 7

Circuit Description

The remote control door lock receiver (RCDLR) communicates with the body control module (BCM) through the keyless entry serial data circuit When any button on the keyless entry transmitter is pressed, the transmitter sends a signal to the RCDLR. The RCDLR sends a lock, unlock, rear release, or panic alarm request to the BCM, depending on which button is pressed on the transmitter. The BCM receives the massage and performs the appropriate function. The BCM also uses the keyless entry serial data circuit in order to communicate with the RCDLR when programming transmitters.

Conditions for Running the DTC

1. The ignition is ON.
2. The system voltage is at least 9.0 volts and not more than 16.0 volts.

Conditions for Setting the DTC

1. The keyless entry serial data circuit is shorted to ground.
2. The above condition must be met for approximately 300 milliseconds.

Action Taken When the DTC Sets

The keyless entry system will not operate.

Conditions for Clearing the DTC

1. A current DTC will clear when the fault is not longer present and the ignition switch is cycled.
2. A history DTC will clear after 100 consecutive ignition cycles with out a fault present.
3. A scan tool may be used to clear history and current DTC(s).

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Remote Keyless Entry System. Refer to «CHECKING AFTERMARKET ACCESSORIES»(ref-175672-S27030348872005042500000) .
2. Inspect the easily the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. See «Panic Mode Inoperative»(ref-176703-S08222087132005051200000) .
2. See «Keyless Entry System Inoperative»(ref-176703-S09092058362005051200000) .
3. See «Door Unlock Function Inoperative With Transmitter»(ref-176703-S01814706722005051200000) .

Scheme 8

Transmitter Programming Procedure (Method 2 - Scan Tool Required)

1. Install a scan tool.
2. Turn the ignition ON, with the engine OFF.
3. Use the scan tool in order to access the Body Control Module (BOM) Special Function: Program Key Fobs menu.
4. Follow the directions on the scan tool in order to program the transmitters.
5. Operate the transmitter functions in order to verify correct system operation.

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

Keyless entry can operate the following components

1. The door locks
2. The interior lamps
3. The parking lamps
4. The headlamps
5. The puddle lamps of equipped)
6. The horn

The keyless entry system has the following main components

1. The transmitters
2. The remote control door lock receiver (RCDLR)

The RCDLR communicates with the body control module (BCM) through the keyless entry serial data circuit. When you press a button on a transmitter, the transmitter sends a signal to the RCDLR. The RCDLR sends a request to the BCM and the BCM performs the appropriate function.