The keyless entry system is a vehicle entry device. The keyless entry will unlock/unlatch the vehicle doors or open the rear gate when a corresponding button on the key fob is pressed. This is accomplished by the key fob sending a radio frequency to the liftgate module (LGM). The signal is received by the LGM via an internal antenna located within the LGM. The LGM 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.

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.

Schematic Reference

Remote Function Schematics

Connector End View Reference

Remote Function Connector End Views

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

Special Tools Required

J 43241 Keyless Entry Tester

1. Place the transmitter on the test pad of the J 43241 and press each button of the transmitter one at a time. The tester should sound a tone and illuminate a green light when the panic button is pressed.

⇒	If the tone does not sound and the green light does not illuminate, replace the transmitter.

2. Verify the scan tool Last FOB Button Pressed parameter responds to the panic function on the transmitter.

⇒	If it does not respond to the panic function, replace the LGM module.

3. Verify that the headlamps pulse ON and OFF when the panic button is pressed.

⇒	If they do not pulse ON and OFF, refer to Diagnostic Starting Point - Lighting Systems .

4. Refer to Diagnostic Starting Point - Horns .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.