For 1990-2009 cars

### DTC Descriptors

DTC B1259 02: Antenna Ground Circuit Short to Ground
DTC B1259 05: Antenna Ground Circuit Short to Battery or Open

### Circuit/System Description

The antenna signal circuit is a coaxial cable that carries the radio signal information received by the antenna to the digital radio receiver (DRR).

### Conditions for Running the DTC

This test is run every 300 milliseconds.

### Conditions for Setting the DTC

The 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

#### Connector End View Reference

Entertainment/Communication Connector End Views

#### Description and Operation

Radio/Audio System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Special Tools Required

EL-48028 Digital Radio Test Antenna

### Circuit/System Testing

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

⇒ | If the DTC B1259 is still current, replace the DRR.

3. Ignition 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 after completing the diagnostic procedure.

• | Digital Radio Antenna Cable Replacement

• | Cellular and Navigation Antenna Assembly Replacement

• | Control Module References for DRR replacement, setup, and programming