For 1990-2009 cars

### 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.

• | Diagnostic Procedure Instructions 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

### Circuit/System Description

The digital radio receiver (DRR) receives digital radio information from a specific digital radio antenna located on the outside of the vehicle. The DRR is connected to the digital radio antenna via a shielded coaxial cable. The antenna cable also provides a path for DC current for powering the antenna.

### 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

#### Connector End View Reference

Component 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

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

EL-48028 Digital Radio Test Antenna

### Circuit/System Testing

Important:

• | Ensure the vehicle is outside in an area with an unobstructed view of the southern sky. Turn XM radio ON. Tune the radio to satellite channel 1. XM reception should be clear.

• | Contact XM radio services at 1-800-852-9696 to verify the customers account status or possible network problems.

1. Ignition OFF, disconnect the antenna coax from the DRR.
2. Connect the EL-48028 to the DRR and place it on the roof of the vehicle.
3. Ignition ON, radio tuned to XM, verify XM reception has improved.

⇒ | If the XM reception has not improved, replace the DRR.

4. Ignition OFF, disconnect the antenna coaxial cable from the DRR antenna base.
5. Test for less than 5 ohms between the two ends of the coax cable center conductor.

⇒ | If greater than the specified range, replace the antenna coax cable.

6. Test for less than 5 ohms between the two ends of the coax cable outer shield.

⇒ | If greater than the specified range, replace the antenna coax able.

7. Test for infinite resistance between the antenna coax center conductor and the outer shield.

⇒ | If less than the specified range, replace the antenna coax cable.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Digital Radio Antenna Replacement

• | Digital Radio Antenna Cable Replacement

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