B125C

DTC B125C

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 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, located inside the radio, receives digital radio information from the digital radio antenna located on the outside of the vehicle. The digital radio receiver 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

* A current DTC clears when the condition for setting the DTC is no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.

Reference Information
Schematic Reference

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

Component Connector End Views Connector Views
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

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 disconnect the digital radio 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 DTC B125C is not set as current and XM reception is improved.

• If DTC B125C is set as current or the reception is not improved, replace the radio.

3. Ignition OFF, reconnect the antenna coax cable at the radio. Disconnect the antenna coax cable from the digital radio antenna.
4. Ignition ON, radio ON, test for 4.5-5.5 V between the antenna coax cable center terminal and an outer shield.

• If less than the specified range, test the antenna coax cable for an open/high resistance.
• If greater than the specified range, test the antenna coax cable for a short to voltage.

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.

* Digital Radio, Mobile Telephone, and Vehicle Location Base Replacement Digital Radio, Mobile Telephone, and Vehicle Location Base Replacement
* Control Module References Control Module References for radio replacement, setup, and programming