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.

### DTC Descriptor

DTC B3976 00: Unconfigured Transponder

### Circuit/System Description

When the body control module (BCM) is in the learn coded key state, the BCM checks the current key to ensure it has been configured as a proper vehicle key.

### Conditions for Running the DTC

• | Ignition is in the Accessory or Run position.

• | The BCM is in the learn coded key state.

### Conditions for Setting the DTC

The BCM has determined the current key is not configured as a proper vehicle key.

### Action Taken When the DTC Sets

• | Vehicle starting will be disabled.

• | The security indicator in the instrument cluster will be illuminated. A service message will be displayed in the driver information center.

### Conditions for Clearing the DTC

• | A current DTC will be cleared when the BCM detects a properly configured vehicle key.

• | A history DTC will be cleared after 100 malfunction-free ignition cycles or when a scan tool is used to clear DTCs.

### Reference Information

#### Schematic Reference

Immobilizer Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Immobilizer 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

### Circuit/System Verification

While viewing DTCs with a scan tool, attempt to start the vehicle using all of the available keys. The vehicle should start with all available keys.

⇒ | If any key results in inoperative starting and DTC B3976 is set as current, replace the appropriate key.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Replacing Keys