For 1990-2009 cars

### Diagnostic Instructions

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

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | 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/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 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.

### Diagnostic Aids

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.

### Reference Information

#### Schematic Reference

Remote Function Schematics

#### Connector End View Reference

Remote Function Connector End Views

#### Description and Operation

Keyless Entry System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Testing

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 none of the buttons sounds the tone and illuminates the green light, replace the battery.

⇒ | If one or more of the buttons sounds the tone and illuminates the green light, replace the transmitter.

4. Verify the scan tool FOB Function parameter responds to every function on the transmitter.

⇒ | If it does not respond to every function, replace the RCDLR module.

5. Replace the transmitter.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Transmitter Programming for transmitter programming

• | Control Module References for RCDLR replacement, setup, and programming