B2485

DTC B2485

Diagnostic Instructions

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

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

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC B2485 02
- Wireless Communication (BT) Antenna Circuit Short to Ground

DTC B2485 04
- Wireless Communication (BT) Antenna Circuit Open

Diagnostic Fault Information






Circuit/System Description

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

Conditions for Running the DTC

* The ignition is in OFF, ACCESSORY or RUN position.

* The system voltage is between 9-16 V.

* The telematics communication interface control module tests the antenna once every second.

Conditions for Setting the DTC

B2485 02

* The signal voltage is less than 1 V.

* The above conditions must be met for 500 ms.

B2485 04

* The signal voltage is greater than 2 V.

* The above conditions must be met for 500 ms.

Actions Taken When the DTC Sets

* The OnStar (R) status LED turns red.

* Bluetooth (R) 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.

Reference Information

Schematic Reference

OnStar Schematics OnStar Schematics

Connector End View Reference

Component Connector End Views Connector End Views By Name

Description and Operation

OnStar Description and Operation OnStar

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Circuit/System Verification

1. Ignition ON.

2. Verify that DTC B2458 is not set.

• If DTC B2485 is set
Refer to Circuit/System testing

• If DTC B2485 is not set

3. All OK.

Circuit/System Testing

1. Verify that the T4S wireless communication antenna - Bluetooth (R) is properly connected to the K73 telematics communication interface control module and is not damaged.

• If the antenna is disconnected
Connect the T4S Bluetooth (R) antenna to the module.

• If the antenna is damaged
Test or replace the T4S Bluetooth (R) antenna

• If the antenna is connected and not damaged

2. Ignition ON.

3. Verify DTC B2485 is not set.

• If the DTC is set

1. Test or replace the T4S Bluetooth (R) antenna.

2. Clear the DTC, ignition OFF.

3. Ignition ON.

4. Verify the DTC is not set.

• If the DTC is set
Replace the K73 telematics communication interface control module.

• If the DTC is not set

5. All OK.

• If the DTC is not set

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Wireless Communication Interface Antenna Replacement Service and Repair

* Control Module References Programming and Relearning for telematics communication interface control module replacement, programming and setup.