B1259

DTC B1259

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) provides an overview of each diagnostic category.

DTC Descriptor
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 an XM satellite radio signal via the digital radio antenna. This signal is passed to the DRR through the digital radio antenna coax. The DRR sends a varying AC mV signal through separate left and right audio circuits (+ and -) to the radio. The voltage amount and rate of change is dependent upon the type of signal being received. The radio then processes these signals and passes the audio to the appropriate speakers or amplifier.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

B1259 02

The DRR detects a short to ground in the antenna circuit.

B1259 05

The DRR detects a short to voltage or an open in the antenna circuit.

Action Taken When the DTC Sets

The radio displays No XM Signal.

Conditions for Clearing the DTC

* A current DTC will clear when the conditions for setting the DTC are no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.

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.

Reference Information
Schematic Reference

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

Component Connector End Views (Connector End Views By Name)
Description and Operation

Radio/Audio System Description and Operation (Radio/Audio System)
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)

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. Radio ON, tuned to XM, 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