Buick Regal: DTC B2485

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.
• Refer to 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

Bluetooth  wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The operating range of the signal is approximately 30 feet.

The Bluetooth  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  enabled cellular phone.

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  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.

Diagnostic Aids

• Verify the mobile device is properly configured for the feature being used. Refer to the device manufacturers information.
• Verify the function/feature that is being used is supported by the mobile device.
• The device must be paired to the telematics communication interface control module to use the available Bluetooth  feature (s). The pairing process must only be performed once for each device, unless that device's information is deleted.
• The system can store pairing information for multiple devices, but can only be actively connected to one at any given time.

Reference Information

Schematic Reference

OnStar/Telematics Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

OnStar Description and Operation (UE1 with IOB/IO6) , OnStar Description and Operation (UI3) , or OnStar Description and Operation (UE1 without IOB/IO6).

Electrical Information Reference

• Refer to Circuit Testing
• Refer to Connector Repairs
• Refer to Testing for Intermittent Conditions and Poor Connections
• Refer to Wiring Repairs

Special Tools

EL-50334-20 Multi-Media Interface Tester (Multi-Media Interface Tool)

Circuit/System Testing

1. Verify that the T4S Wireless Communication Antenna - Bluetooth  is properly connected to the K73 Telematics Communication Interface Control Module and is not damaged.

• If the antenna is disconnected

Connect the T4S Wireless Communication Antenna - Bluetooth  to the module.

• If the antenna is damaged

Test or replace the T4S Wireless Communication Antenna - Bluetooth Â.

• Go to next step: If the antenna is connected and not damaged

NOTE: The Multi-Media Interface Tool can be used to test either cellular phone or streaming audio functions. Refer to the tool instructions, and perform the appropriate test (s) related to the customers concern in the following steps.

2. Ignition ON, infotainment system ON.

3. Verify the infotainment system successfully pairs with the Multi-Media Interface Tool.

• If the infotainment system does not successfully pair with the Multi-Media Interface Tool.

1. Test or replace the T4S Wireless Communication Antenna - Bluetooth Â.
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.
   • Go to next step: If the DTC is not set
5. All OK.

• Go to next step: If the infotainment system successfully pairs with the Multi-Media Interface Tool.

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

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