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.
Diagnostic Fault Information
Circuit/System Description
AM and FM radio reception is dependent on the following components:
* Radio antenna in the rear glass
* Radio antenna module
* Coax cable between the radio antenna and the radio antenna module
* Radio
The antenna amplifier receives both AM and FM signals from the rear glass antenna. The radio antenna amplifier is enabled when the radio is turned on. The radio provides battery voltage to the antenna amplifier using the center conductor of the antenna coaxial cable. When a 12 V signal is seen by the module on the center conductor of the antenna coax, both AM and FM signals are amplified.
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. Aftermarket window tinting, especially when there is a metallic in the film, may reduce radio reception.
Reference Information
Schematic Reference
Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Radio/Audio System Description and Operation (Radio/Audio System)
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 (Programming and Relearning)for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the radio antenna coax from the A11 radio and from the radio antenna amplifier.
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 ohm on the antenna coax center circuit from end to end.
• If greater than the specified range, replace the antenna coax.
4. Ignition ON, test for less than 1 V between the antenna coax center terminal and ground.
• 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. Connect the antenna coax to the A11 radio. Test for 12-15 V between the antenna coax center terminal and ground at the radio antenna amplifier connector.
• If not within the specified range, replace the A11 radio.
7. If all circuits test normal, replace the radio antenna amplifier.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Radio Antenna Amplifier Replacement (Radio Antenna Amplifier Replacement)
Control Module References (Programming and Relearning)for radio replacement, setup, and programming