B1259

DTC B1259

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 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".

Conditions for Clearing the DTC

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

Circuit/System Testing

1. Ignition OFF, disconnect the DRR antenna coaxial cable 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 radio antenna base from the DRR coaxial cable. Test the resistance of the DRR 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 DRR antenna coaxial cable.

4. Test the resistance of the DRR 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 DRR antenna coaxial cable.

5. Test the resistance of the DRR 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 DRR antenna coaxial cable, replace the DRR antenna coaxial cable. If the DRR antenna coaxial cable tests normal, replace the radio antenna base.

Repair Instructions

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

* Digital Radio Antenna Cable Replacement
* Digital Radio Antenna Replacement