Radio Poor Reception

Radio Poor Reception

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* 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 (if equipped).
* Radio antenna module (if equipped)
* Coax cable between the radio antenna module and the radio
* 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 the 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.


Circuit/System Testing

Antenna Coaxial Cable Testing
1. The antenna coax may have one or two sections between the radio and the mast antenna.

Important: For steps 2 - 6, perform the tests on each of the disconnected coax cables.

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

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 of resistance 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 of resistance 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.

Rear Glass Antenna Inspection
1. Ignition OFF, disconnect the coax from the antenna located at the rear glass.
2. Verify the coax connector at the back glass is properly secured and free of any damage.

• If damage is found, repair or replace as necessary.

3. Inspect the antenna on the rear glass. Verify all branches of the antenna are intact, with no scratches or other damage.

• If damage is found, repair or replace as necessary.

Repair Instructions

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

* Radio Antenna Replacement