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 Descriptors
DTC B1259 02
- Antenna Ground Circuit Short to Ground

DTC B1259 05
- Antenna Ground Circuit Short to Battery or Open




Diagnostic Fault Information






Circuit/System Description

The digital radio receiver (DRR) receives XM satellite radio signals via a digital radio antenna located on the outside of the vehicle. The signal is passed to the DRR through digital radio antenna coax. From the DRR, one audio common (-) and separate left and right audio signals (+), are sent to the radio. The radio processes these signals and passes the audio to the appropriate speakers or audio amplifier.


Diagnostic Aids

When diagnosing digital radio concerns, the vehicle should be located outside with an unobstructed view of the southern sky to ensure proper reception of the satellite signal. Reception may limited, intermittent or not possible inside structures or under heavy cover.


Conditions for Running the DTC

* Radio ON.
* Battery voltage must be between 9-16 volts.



Conditions for Setting the DTC

B1259 02

The DTC will set when the DRR detects a short to ground in the antenna ground circuit.

B1259 05

The DTC will set when the DRR detects a short to voltage or an open/high resistance in the antenna ground circuit.


Actions Taken When the DTC Sets

* Digital radio reception may be poor or not available.
* The radio displays "No XM Signal" or "Check Antenna".



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

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

With the vehicle outside in an area with an unobstructed view of the southern sky, tune to XM. Verify XM reception is clear and the No XM Signal message is not displayed on the radio.


Circuit/System Testing

1. Ignition OFF, disconnect the antenna coax from the DRR. Connect the EL-48028 to the DRR.
2. Ignition ON, radio tuned to XM, verify verify DTC B1259 is not set as current.

• If the DTC is current, replace the DRR.

3. Ignition OFF, reconnect the antenna coax to the DRR, disconnect the digital radio antenna coax from the digital radio antenna.
4. Ignition ON, test for 4.5-5.5 volts between the antenna coax center terminal and the coax outer shield.

• If not within the specified range, replace the antenna coax.

5. If all circuits test normal, replace the digital radio antenna.



Repair Instructions

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

* Cellular Communications/Digital Radio Antenna Replacement (Cellular Communications/Digital Radio Antenna Replacement)
* Control Module References (Programming and Relearning) for DRR replacement, setup, and programming