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Home >> Pontiac >> 2009 >> G8 Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 473 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> Radio Poor Reception >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Inspect the radio antenna branches on the rear glass for damage.
    • If damage is found, repair or replace as necessary.
  2. Inspect the radio antenna module grounding surface and the mounting hardware for any corrosion that may cause a poor ground.
    • If corrosion is noted, clean the grounding surfaces and hardware.
  3. Disconnect the front antenna coax cable from the radio antenna module and the antenna.
  4. Test for infinite resistance between the antenna coax center terminal and ground.
    • If less than the specified value, replace the antenna coax.
  5. Test for less than 5Ω on the antenna coax center terminal from end to end.
    • If greater than the specified range, replace the antenna coax.
  6. Test for less than 5Ω on the antenna coax outer shield from end to end.
    • If greater than the specified range, replace the antenna coax.
  7. Test for infinite resistance between the coax center terminal and the outer shield.
    • If less than the specified value, replace the antenna coax.
  8. Ignition OFF, disconnect the C1 harness connector at the radio antenna module.
  9. Radio ON, test for B+ between the signal circuit terminal 1 and ground.
    • If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  10. Radio tuned to FM, test for 4.5 - 8.5V on the FM composite signal terminal 2.
    • If less than specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the radio.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  11. Ignition OFF, reconnect the harness connector at the left antenna module.
  12. Ignition OFF, disconnect the coax cables at the radio and radio antenna module.
  13. Test for infinite resistance between the antenna coax center terminal and ground.
    • If less than the specified value, replace the antenna coax.
  14. Test for less than 5Ω on the antenna coax center terminal from end to end.
    • If greater than the specified range, replace the antenna coax.
  15. Test for less than 5Ω on the antenna coax outer shield from end to end.
    • If greater than the specified range, replace the antenna coax.
  16. Test for infinite resistance between the coax center terminal and the outer shield.
    • If less than the specified value, replace the antenna coax.
  17. Radio ON, verify the radio reception has improved.
    • If there is still poor reception, replace the antenna module.
  18. If all circuits test normal, replace the radio.
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