B1259

DTC B1259

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC B1259
- Antenna Ground Circuit




Diagnostic Fault Information






Circuit/System Description

The antenna signal circuit is a coaxial cable that carries the radio signal information received by the antenna. The antenna cable also provides a path for DC current for powering the antenna.


Conditions for Running the DTC

This test is run every 300 milliseconds.


Conditions for Setting the DTC

The digital radio receiver (DRR) detects an antenna fault.


Action Taken When the DTC Sets

The radio displays "No XM Signal" or "Check Antenna".


Conditions for Clearing the DTC

* The condition must be corrected.
* The DTC clears after 100 malfunction-free ignition cycles.



Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Radio/Audio System Description and Operation (Radio/Audio System Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

EL-48028 Digital Radio Test Antenna


Circuit System Verification

Ignition ON , Radio ON tuned to an XM(TM) station. The vehicle may need to be outside with a clear view of the sky for optimum satellite reception. The XM(TM) radio should play clearly.


Circuit/System Testing

1. Ignition OFF, disconnect the antenna coax from the digital radio receiver (DRR). Connect the test antenna to the DRR.
2. Turn the ignition ON, radio ON tuned to XM(TM). Verify that DTC B1259 is not current.

• If the DTC B1259 is still current, replace the DRR.

3. Ignition is OFF. Disconnect the DRR antenna from the coaxial cable. Test the resistance of the antenna coaxial cable center conductor from end to end. Verify the resistance is less than 5 ohms.

• If the resistance is greater than 5 ohms, replace the antenna coaxial cable.

4. Test the resistance of the antenna coaxial cable outer shield from end to end. Verify the resistance is less than 5 ohms.

• If the resistance is greater than 5 ohms , replace the antenna coaxial cable.

5. Test the resistance of the antenna coaxial cable between the center conductor and the outer conductor. Verify there is infinite resistance between both conductors.

• If there is less than infinite resistance between the inner conductor and the outer conductor of the coaxial cable, replace the antenna coaxial cable. If the coaxial cable tests normal, replace the digital radio antenna.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Digital Radio Antenna Cable Replacement (Digital Radio Antenna Cable Replacement)
* Cellular Communications/Digital Radio Antenna Replacement (Cellular Communications/Digital Radio Antenna Replacement)
* Digital Radio Receiver Replacement (Digital Radio Receiver Replacement)