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

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. An incorrect transmitter may pass the test, but it will not activate the keyless entry system.

Schematic Reference

Remote Function Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Keyless Entry System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 43241 Keyless Entry Tester

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 Battery parameter for the appropriate keyless entry transmitter is OK.

⇒	If no the specified value, replace the transmitter battery.

3. Verify the scan tool Fob Programmed parameter for the appropriate keyless entry transmitter is Yes.

⇒	If no the specified value, program the transmitter. Refer to Transmitter Programming.

4. 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 each button is pressed.

⇒	If one or more buttons does not sound the tone and illuminate the green light, replace the transmitter.

5. Operate the transmitter while observing the scan tool Last Fob Button Pressed parameter. 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.

6. If all circuits test normal, replace the LGM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for LGM replacement, setup, and programming