Radio Poor Reception

Radio Poor Reception

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.



Circuit/System Description

AM and FM radio reception is dependent on the following components:

* Radio antenna
* Coax cable between the radio antenna and the radio antenna module
* 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 not part of the radio system. Such examples are aftermarket electrical accessories or other items which may generated noise in the vehicle electrical system.


Diagnosing a poor reception concern will require a systematic approach to isolating the cause. Individual components should each be tested before proceeding with any repair or replacement.

Using a Test Antenna

Use a test mast antenna to check for poor vehicle antenna operation. Disconnect the antenna coax from the radio and plug the test antenna into radio. Make sure the test antenna base is grounded to the vehicle chassis and keep hands off the mast. Check radio reception in an area away from electrical interferences. Tune to several weak and strong AM and FM stations. If the radio reception improved, the problem exists with the vehicle antenna and/or lead-in cable.


Reference Information
Schematic Reference

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

Component Connector End Views (Component Connector End Views)
Description and Operation

Radio/Audio System Description and Operation (Radio/Audio System Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Inspect the antenna for damage.

If damage found, replace as necessary.


Radio ON, tune to several known FM, AM, and XM (if equipped) stations, and play a known good CD.

If audio output is poor from all sources, refer to Speaker Malfunction (without Navigation Radio) (Speaker Malfunction (without Navigation Radio))Speaker Malfunction (with Navigation Radio) (Speaker Malfunction (with Navigation Radio)) .
If both AM and FM reception is poor, refer to Antenna Circuit Testing.



Circuit/System Testing


Antenna Circuit Testing
1. Ignition OFF, disconnect both ends of the coax from the radio and radio antenna.
Important: For steps 2-5, perform the tests on each of the disconnected coax cables.



2. Test for infinite resistance between the antenna coax center terminal and ground.

• If less than the specified value, replace the antenna coax.

3. Test for less than 5 ohms on the antenna coax center terminal from end to end.

• If greater than the specified range, replace the antenna coax.

4. Test for less than 5 ohms on the antenna coax outer shield from end to end.

• If greater than the specified range, replace the antenna coax.

5. Test for infinite resistance between the coax center terminal and the outer shield.

• If less than the specified value, replace the antenna coax.

6. If all circuits test normal, replace the antenna.
7. Ignition ON, radio ON, verify radio reception has improved.

• If there is still poor reception, replace the radio.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Antenna Cable Replacement (Antenna Cable Replacement)
* Radio Antenna Cable Extension Cable Replacement (Radio Antenna Cable Extension Cable Replacement)
* Control Module References (Programming and Relearning) for radio replacement, setup, and programming