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 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 (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.

### 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.

• | The keyless entry transmitter used in the 2 Way Advanced Remote Start System is unique to the system. When servicing or replacing a transmitter, ensure that the correct trasmitter is used. The correct transmitter part number can be found in the Accessory section of the parts catalog. Attempting to replace an 2 Way Advanced Remote Start transmitter with a regular service part may result in a failure to program the trasmitter.

### Reference Information

#### 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

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

J 43241 Keyless Enter Tester

### Circuit/System Verification

Attempt to program the keyless entry transmitter, refer to Transmitter Programming . 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. Verify the scan tool FOB Programmed parameter for the appropriate transmitter is Yes.

⇒ | If not the specified value, program the transmitter. Refer to Transmitter Programming .

3. 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.

4. Operate the transmitter while observing the scan tool 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.

5. If all circuits test normal, replace the RCDLR.

### Repair Instructions

Important: This vehicle may be equipped with the 2 Way Advanced Remote Start System. Vehicle equipped with the 2 Way Advanced Remote Start System can be identified by an LCD screen on the keyless entry transmitter or a yellow label on the RCDLR. When servicing the 2 Way Advanced Remote Start System, ensure that the correct parts are installed during replacement. Service parts for the 2 Way Advanced Remote Start System can be found in the Accessory section of the parts manual.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Transmitter Programming

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