Keyless Entry System Malfunction

Keyless Entry System Malfunction

Diagnostic Instructions

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

Circuit/System Description

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, which then sends the signal to the body control module (BCM). The BCM interprets the signal and activates the requested function. 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

* When using the J 43241 Keyless Entry Tester, first inspect the keyless entry transmitter part number to determine that it is the correct model for the vehicle. An incorrect part number transmitter may pass the test, but it will not activate the keyless entry system.
* When the vehicle key is in the ignition, the keyless entry functions are disabled from the keyless entry transmitter.

Reference Information
Schematic Reference

Remote Function Schematics (Electrical Diagrams)
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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Attempt to learn the keyless entry transmitter, refer to Replacing Keys (Replacing Keys). 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. 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.

3. Operate the transmitter while observing the appropriate scan tool Key Fob Function parameter for the appropriate 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 and retest. If the conditions continues after transmitter replacement, replace the K9 BCM.

Repair Instructions

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

* Replacing Keys (Replacing Keys)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming