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 - part of the rear glass

* Radio antenna module

* Coax cable between the radio antenna module and the radio

* Radio

Diagnostic Aids

Note:
Radio systems with the antenna(s) in the glass are subject to possible interference when an aftermarket window tint is applied, especially when there is a metallic present in the film.

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.

AM reception is highly dependent on the antenna module receiving battery voltage from the radio and being properly grounded. The antenna module has a built in antenna amplifier that boosts both AM and FM reception. When the antenna module does not receive power, AM stations will not be received and FM reception will be limited. If the module is not properly grounded, excessive interference in the signal may occur, or reception may be limited.

Reference Information

Schematic Reference

Radio/Navigation System Schematics Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views A/C Compressor Clutch

Description and Operation

Radio Rear Speaker Replacement (Impala w/UQ3) Radio Rear Speaker Replacement (Impala w/UQ3)Radio Rear Speaker Replacement (Impala w/UW6) Radio Rear Speaker Replacement (Impala w/UW6)

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Testing

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.

Antenna Coaxial Cable Testing

1. Disconnect the antenna coax from the radio and the radio antenna module.

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.

Radio Antenna Module Test

1. Inspect the radio antenna module grounding surfaces and the mounting hardware for any corrosion that may cause a poor ground.

• If corrosion is noted, clean the grounding surfaces or hardware.

2. Ignition OFF, disconnect the harness connector at the radio antenna module.

3. Radio ON, verify a test lamp illuminates between the signal circuit terminal 1 and ground.

• If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

4. If all circuits test normal, replace the radio antenna module.

Repair Instructions

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

* Radio Antenna Module Replacement Radio Antenna Module Replacement

* Antenna Cable Replacement Antenna Cable Replacement

* Radio Antenna Cable Extension Cable Replacement Radio Antenna Cable Extension Cable Replacement

* Control Module References Control Module References for radio replacement, setup, and programming