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 provide an overview of each diagnostic category.

### DTC Descriptors

DTC B2485 02: Wireless Communication Antenna Circuit (Bluetooth) Short to Ground
DTC B2485 04: Wireless Communication Antenna Circuit (Bluetooth) Open Circuit

### Circuit/System Description

The Bluetooth ® antenna is a small fixed antenna connected directly to the communication interface module (CIM) and is used to send and receive signals from a Bluetooth ® enabled cellular phone. The antenna utilizes no cabling and is not external to the vehicle.

### Conditions for Running the DTC

• | Ignition ON.

• | Battery voltage must be between 9-16 volts.

• | The CIM tests the antenna once every second.

### Conditions for Setting the DTC

#### B2485 02

The CIM detects a short to ground in the Bluetooth ® antenna.

#### B2485 04

The CIM detects an open/high resistance in the Bluetooth ® antenna.

### Actions Taken When the DTC Sets

• | The OnStar ® status LED turns red.

• | Bluetooth ® functionality is disabled.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

#### Schematic Reference

OnStar Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

OnStar 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 Testing

1. Verify the Bluetooth ® antenna is properly connected to the CIM and is not damaged.

⇒ | If the antenna is disconnected or damaged, repair or replace as necessary.

2. Ignition ON, verify the DTC B2485 is not set.

⇒ | If the DTC is set, replace the Bluetooth ® antenna. Clear the DTC and cycle the ignition OFF then back ON. If the DTC resets as current, replace the CIM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Wireless Communication Interface Antenna Replacement

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