For 1990-2009 cars

### Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle .

### Circuit/System Description

Some models are fitted with a dual antenna system, called Main and Diversity antennas respectively. When testing the antenna systems it is useful to command to the infotainment unit which antenna to use when making comparisons in signal quality between the two systems. The Antenna selection test is performed using a scan tool.

### Diagnostic Aids

• | This diagnostic is for the infotainment units dual antenna system feature.

• | Before diagnosis of the speed dependent volume feature, make sure the primary controls of the associated components are functioning properly.

### Reference Information

#### Scan Tool Reference

Control Module References

### Component Testing

Important: It is recommended that component testing is performed before circuit testing when diagnosing infotainment unit functions.

1. Connect a scan tool to the DLC and select Infotainment System / Audio System / Actuator Test / Tuner / Antenna .
2. Switch the infotainment unit on and select a strong local FM radio station frequency. Set the volume to a comfortable listening level.
3. Use the Main soft key on the scan tool to select the main antenna. Verify the scan tool screen displays the appropriate antenna selection.
4. From the Body menu select Data Display / Data List , then use the Down arrow key on the scan tool to scroll to Antenna and verify the Main antenna is selected.
5. Use the Down arrow key on the scan tool to scroll to Antenna Signal Strength and note the signal strength indication.
6. On the scan tool select Infotainment System / Audio System / Actuator Test / Tuner / Antenna .
7. Use the Diversity soft key on the scan tool to select the diversity antenna. Verfy the scan tool screen displays the appropriate antenna selection.
8. From the Body menu select Data Display / Data List , then use the Down arrow key on the scan tool to scroll to Antenna and verify the Diversity antenna is selected.
9. Use the Down arrow key on the scan tool to scroll to Antenna Signal Strength and note the signal strength indication.
10. Compare the signal strength figures to provide an objective comparison of antenna performance.
11. Press the Quit soft key to exit the test. The Main antenna will be selected on exiting the test.

⇒ | If the Antenna Selection function does not operate correctly, replace the infotainment unit.

### Repair Instructions

Perform the Diagnostic Repair Verification .

Radio Replacement