Contents Wiring diagrams Section: Door Locks & Anti-Theft Systems All sections

Keyless Entry System and Remote Functions: Diagnosis Chevrolet Silverado Classic 1500 HD

Diagnostic Starting Point - Remote Functions

Begin the system diagnosis with Diagnostic System Check - Vehicle . The Diagnostic System Check will provide the following information

  1. The identification of the control modules which command the system
  2. The ability of the control modules 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 procedure for diagnosing the system and where the procedure is located.

Scan Tool Output Controls

Scan Tool Output ControlAdditional Menu SelectionsDescription
Special FunctionsProgram All Key FobsThe Passenger door module will erase all previously programmed key fobs and then program the first fob as Fob 1, the next fob as Fob 2,and any additional fobs as Fob 3 and Fob 4.
Special FunctionsProgram Individual Key FobThe Passenger door module will program a key fob to any one of 4 possible positions: Key Fob 1-4.

Scan Tool Output Controls

Scan Tool Data List

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Ignition ON, Engine OFF
Fob 1 BatteryPassenger Door Module DataOK, LowOK
Fob 2 BatteryPassenger Door Module DataOK, LowOK
Fob 3 BatteryPassenger Door Module DataOK, LowOK
Fob 4 BatteryPassenger Door Module DataOK, LowOK
Last Fob Button PressedPassenger Door Module DataLock, Unlock, PanicUnlock
Last FOB UsedPassenger Door Module DataFOB 1-4FOB 1
Fob 1 ProgrammedPassenger Door Module DataYes, NoYes
Fob 2 ProgrammedPassenger Door Module DataYes, NoYes
Fob 3 ProgrammedPassenger Door Module DataYes, NoNo
Fob 4 ProgrammedPassenger Door Module DataYes, NoNo

Scan Tool Data List

Symptoms - Remote Functions

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform «Diagnostic System Check - Vehicle»(ref-277883-S07139257572008012100000) , before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Keyless Entry System Description and Operation»(ref-277860-S10182100902008012100000) and «Garage Door Opener Description and Operation»(ref-277860-S10926743262008012100000) .

Visual/Physical Inspection

  1. Turn the ignition key to the ON position and press any garage door opener (GDO) button. The LED should light when the unit has power and is functional.
  2. Inspect for aftermarket devices which could affect the operation of the Keyless Entry System or the Garage Door Opener. Refer to «Checking Aftermarket Accessories»(ref-277884-S30236091172008012100000) .
  3. Inspect 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. «Garage Door Opener Inoperative»(ref-277860-S26246341262008012100000)
  2. «Keyless Entry System Inoperative»(ref-277860-S39436762482008012100000)
  3. «Panic Mode Inoperative»(ref-277860-S36224038132008012100000)

Method 2 - Scan Tool Required, Program Individual Transmitter

IMPORTANTAll transmitters which are to be recognized by the PDM must be programmed in a single programming sequence. When using this program method, all previously programmed transmitters will be erased upon the receipt of the programming signal from the first transmitter. The order in which the transmitters are programmed will determine its numbering position within the PDM memory. The first transmitter programmed will be transmitter #1, and the second transmitter programmed will be transmitter #2. The number stamped on the transmitter case is for reference only; #2 can be programmed as #1, or vice versa. Additional unnumbered transmitters are also available.

Only use this option if you are certain which transmitter, #1-#4, is being replaced, or the new transmitter can be programmed into a previously unused position within the PDM memory.

  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Use the scan tool in order to access the passenger door module Special Function menu.
  4. Select Program Individual Key Fob to program specific transmitters.
  5. Follow the directions on the scan tool in order to program the transmitter or transmitters.
  6. Operate the transmitter functions in order to verify correct system operation.

Method 3 - Scan Tool Required, Program All Transmitters

IMPORTANTAll transmitters which are to be recognized by the PDM must be programmed in a single programming sequence. When using this program method, all previously programmed transmitters will be erased upon the receipt of the programming signal from the first transmitter. The order in which the transmitters are programmed will determine its numbering position within the PDM memory. The first transmitter programmed will be transmitter #1, and the second transmitter programmed will be transmitter #2. The number stamped on the transmitter case is for reference only; #2 can be programmed as #1, or vice versa. Additional unnumbered transmitters are also available.
  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Use the scan tool in order to access the passenger door module Special Function menu.
  4. Select Program All Key Fobs to clear the PDM memory.
  5. Follow the directions on the scan tool in order to program the transmitters.
  6. Operate the transmitter functions in order to verify correct system operation.