Diagnostic Instructions

DTC Descriptors

DTC B125C 01: Satellite Antenna 1 Circuit Short to Battery

DTC B125C 02: Satellite Antenna 1 Circuit Short to Ground

DTC B125C 04: Satellite Antenna 1 Circuit Open Circuit

Circuit/System Description

The digital radio receiver (DRR), located inside the radio, receives digital radio information from the digital radio antenna located on the outside of the vehicle. The DRR is connected to the digital radio antenna via a shielded coax cable.

Conditions for Running the DTC

This DTC is run every 300 milliseconds.

Conditions for Setting the DTC

The radio detects a circuit fault in the digital radio antenna.

Action Taken When the DTC Sets

The radio displays No XM Signal or Check Antenna.

Conditions for Clearing the DTC

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

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 DRR antenna coax from the radio. Connect the EL-48028 to the radio and place on the roof of the vehicle.
2. Ignition ON, radio tuned to XM channel 1. Verify XM reception is improved.

⇒	If the reception is not improved, replace the radio.

3. Ignition OFF, disconnect the antenna coaxial from the digital radio antenna.
4. Ignition ON, test for 4.5-5.5 volts between the antenna coax center terminal and ground.

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

5. Test for infinite resistance between the antenna coax center terminal and ground.

⇒	If not the specified value, replace the antenna coax.

6. Test for less than 5 ohms end to end at the coax center conductor.

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

7. Test for less than 5 ohms end to end at the coax outer shield.

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

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

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

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.