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 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 fob/key is pressed. This is accomplished by the keyless entry fob/key 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 fob/key 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.

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 fob/key, refer to Replacing Keys (Erases All Existing Keys) (Replacing Keys (Erases All Existing Keys)). The fob/key should learn.

Circuit/System Testing

1. Verify that the fob/key is the correct fob/key for the vehicle.

• If not the correct fob/key, replace the fob/key.

2. Place the fob/key on the test pad of the J 43241 and press each fob/key 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 fob/key battery and retest with the J 43241. If the condition continues after battery replacement, replace the fob/key.

3. Operate the fob/key while observing the scan tool Fob Function parameter for the appropriate fob/key. The parameter should correspond with the function selected on the fob/key.

• If the parameter does not match the function selected on the fob/key, replace the fob/key.

4. Attempt to learn the fob/key, refer to Replacing/Adding Keys. The fob/key should learn.

• If the fob/key does not learn, test the keyless entry antenna for an open/high resistance. If the circuit tests normal, replace the K9 BCM.

Repair Instructions

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

* Replacing Keys (Erases All Existing Keys) (Replacing Keys (Erases All Existing Keys))
* Control Module References (Programming and Relearning) for remote control door lock receiver replacement, setup, and programming