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 Descriptors

DTC B2483: GPS Sensor Circuit Low
DTC B2484: GPS Sensor Circuit Open

### Circuit/System Description

The vehicle communication interface module (VCIM) receives information from a specific GPS antenna located on the outside of the vehicle. The GPS antenna is connected to the VCIM via a shielded coaxial cable. The antenna cable also provides a path for DC current for powering the antenna.

### Conditions for Running the DTC

• | Ignition is in the RUN or ACC position.

• | Battery voltage is between 9-16 volts.

### Conditions for Setting the DTC

#### B2483 00

The VCIM detects a short to ground on the GPS antenna signal circuit.

#### B2484 00

The VCIM detects an open/high resistance on the GPS antenna signal circuit.

### Action Taken When the DTC Sets

• | The OnStar® status LED turns red.

• | The OnStar® Call Center cannot locate the vehicle.

### Conditions for Clearing the DTC

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

• | A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

### Reference Information

#### 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

### Circuit/System Testing

1. Disconnect the harness connector at the radio antenna.
2. Ignition OFF, test for less than 10 ohms between the terminal 4 outer shield and ground.

⇒ | If greater than the specified range, test the antenna coax shield for an open/high resistance. If the coax tests normal, replace the VCIM.

3. Ignition ON, test the terminal 4 center terminal for 4.5-5.5 volts.

⇒ | If greater than the specified range, test the antenna coax center terminal for a short to voltage. If the coax tests normal, replace the VCIM.

⇒ | If less than the specified range, test the antenna coax center terminal for a short to ground or an open/high resistance. If the coax tests normal, replace the VCIM.

4. If all circuits test normal, replace the antenna.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Radio Antenna Replacement

• | Antenna Cable Replacement

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