GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 CTS 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Digital Radio Poor or No Reception

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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Digital Radio Antenna Coax

1

1

1

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1. Poor or no digital radio reception

Circuit/System Description

The XM satellite radio is integrated into the radio. The radio receives an XM satellite radio signal via the digital radio antenna. This signal is passed to the DRR through the digital radio antenna coax. The antenna cable also provides a path for D.C. current for powering the antenna.

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 Verification
  1. Tune to a strong AM or FM station and verify each speaker is producing clear and even sound, with no distortion.
    2. ⇒If any speaker is not producing sound or the sound produced is distorted, refer to Speaker Malfunction.
  2. 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 digital radio antenna coax from the radio. Connect the EL-48028 to the radio and move the vehicle outside in an area with an unobstructed view of the southern sky.
  2. Ignition ON, radio tuned to XM, verify XM reception is clear and uninterrupted.
    3. ⇒If reception is not clear, replace the radio.
  3. Ignition OFF, disconnect the digital radio antenna coax from the radio and from the digital radio antenna.
  4. Ignition ON, test for less than 1 volt between the antenna coax center terminal and ground.
    5. ⇒ If greater than the specified range, replace the antenna coax.
  5. Test for infinite resistance between the antenna coax center terminal and ground.
    6. ⇒ If less than the specified value, replace the antenna coax.
  6. Test for less than 5 ohms on the antenna coax center circuit from end to end.
    7. ⇒ If greater than the specified range, replace the antenna coax.
  7. Test for infinite resistance between the coax center terminal and the outer shield.
    8. ⇒ If less than the specified value, replace the antenna coax.
  8. If all circuits test normal, test or replace the digital radio antenna.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Mobile Telephone and Vehicle Location Antenna Base Replacement
    •  Control Module References for radio replacement, setup, and programming