Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

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 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.

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

Description and Operation

Keyless Entry System Description and Operation

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

Attempt to program the keyless entry transmitter, refer to Transmitter Programming . The transmitter should program.

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 is Yes.

⇒	If not Yes, program the transmitter.

3. 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 battery and retest with the J 43241 . If the condition continues after battery replacement, replace the transmitter.

4. Attempt to program the transmitter, refer to . The transmitter should program.

⇒	If the transmitter does not program, replace the RCDLR.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.