Keyless Entry System Inoperative

Keyless Entry System Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



Circuit/System Description

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 signal is received by the RCDLR via an internal antenna located within the RCDLR. The RCDLR interprets the signal and activates the requested function via a message over the GMLAN 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.


Diagnostic Aids

For the J 43241 Keyless Entry Tester, inspect the keyless entry transmitter part number to determine that it is the correct model for the vehicle. A wrong model transmitter may pass the test, but it will not activate the vehicle remote system.


Reference Information
Schematic Reference

Remote Function Schematics (Remote Function Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Keyless Entry System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information
Special Tools

J 43241 Keyless Enter Tester


Circuit/System Verification

Attempt to program the keyless entry transmitter, refer to Transmitter Programming (Programming and Relearning). The transmitter should program.


Circuit/System Testing

1. Verify that the transmitter is the correct transmitter for the vehicle.

• If not the correct transmitter, replace the transmitter.

2. Verify the scan tool FOB Programmed parameter for the applicable transmitter is Yes.

• If not the specified value, program the transmitter. Refer to Transmitter Programming (Programming and Relearning).

3. Place the transmitter on the test pad of the J 43241 and press each transmitter button one at a time. The tester should sound a tone and illuminate a green light with each button press.

• If one or more buttons does not sound the tone and illuminate the green light, replace the transmitter battery and retest with the J 43241. If the condition continues after battery replacement, replace the transmitter.

4. Operate the transmitter while observing the scan tool Fob Function parameter for the applicable transmitter. The parameter should correspond with the function selected on the transmitter.

• If the parameter does not match the function selected on the transmitter, replace the transmitter.

5. If all circuits test normal, replace the RCDLR.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Transmitter Programming (Programming and Relearning)
* Control Module References (Programming and Relearning) for RCDLR replacement, setup, and programming