Diagnostic Instructions
Circuit/System Description
AM and FM radio reception is dependent on the following components:
• | Coax cable between the radio antenna and the radio. |
Diagnostic Aids
Poor AM and FM radio reception is dependent on multiple influences, some of which may not be vehicle related. Areas which have high RF traffic or block the signal path may cause a degradation in radio reception. Radio reception may also be influenced by
items within the vehicle, but are not part of the radio system. Such examples are aftermarket electrical accessories or other items which may generate noise in the vehicle electrical system.
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
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Inspect the antenna for proper mounting or physical damage.
⇒ | If damage is found, repair or replace as necessary |
- Radio ON, tune to several known FM, AM, and XM (if equipped) stations, and play a known good CD.
Circuit/System Testing
Antenna Circuit Testing
- Ignition OFF, disconnect the radio antenna coax cable from the radio and the radio antenna.
- Test for infinite resistance between the antenna coax center terminal and ground.
⇒ | If less than the specified value, replace the antenna coax. |
- Test for less than 10 Ω on the antenna coax center terminal from end to end.
⇒ | If greater than the specified range, replace the antenna coax. |
- Test for less than 10 Ω on the antenna coax outer shield from end to end.
⇒ | If greater than the specified range, replace the antenna coax. |
- Test for infinite resistance between the coax center terminal and the outer shield.
⇒ | If less than the specified value, replace the antenna coax. |
- Reconnect the coax to the radio antenna. Test for infinite resistance on the coax at the radio between the center terminal and the outer shield.
⇒ | If less then specified value, replace the antenna. |
- Test for less than 10 Ω on the coax at the radio between the outer shield and ground.
⇒ | If greater than specified value, clean the mounting surface of the antenna ground plane. If no corrosion found, replace the antenna. |
- If all circuits test normal, replace the radio.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.