DTC B125A or B125B. Cadillac XLR 2006

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2006 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC B125A or B125B

DTC Descriptors

DTC B125A: Antenna 1 Circuit left

DTC B125B: Antenna 2 Circuit right

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The antenna signal circuit is a coaxial cable that carries the radio signal information received by the antenna. The antenna cable also provides a path for DC current for powering the antenna. The antenna 1 circuit (left) is the green connector at the digital radio receiver (DRR). The antenna 2 circuit (right) is the curry colored connector at the DRR.

Conditions for Running the DTC

This test is run every 14 seconds.

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

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

Ignition OFF, disconnect the antenna coax from the DRR. Connect the test antenna to the DRR.
Turn the ignition ON, radio ON tuned to XM. Verify that DTC B125A/B is not current.

⇒	If the DTC B125A/B is still current, replace the DRR.

Ignition is 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.

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.

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

•	Outside Rearview Mirror Replacement

•	Digital Radio Receiver Replacement