For 1990-2009 cars

Schematic Reference: Radio/Navigation System Schematics

Connector End View Reference: Entertainment/Communication Connector End Views

### Diagnostic System Check - Vehicle

Always perform the Diagnostic System Check - Vehicle before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Vehicle.

### Left or Right Side - Reduced Volume

Note:

The following information lists the most probable cause of the concern to the least probable cause. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

1. Front Low Level Audio Signal shorted--Test the Left or Right Front Low Level Audio Signal circuit for a short to ground or to voltage. Refer to Circuit Testing and Wiring Repairs.
2. Defective Radio--Replace the Radio. Refer to Control Module References for replacement, setup and programming.
3. Defective amplifier--Replace the amplifier. Refer to Control Module References for replacement, setup and programming.

### Reduced Volume During Digital Surround Sound Enabled DVD

Note: The following information lists the most probable cause of the concern to the least probable cause. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

1. Front Low Level Audio Signal shorted--Test the Left or Right Front Low Level Audio Signal circuit for a short to ground or to voltage. Refer to Circuit Testing and Wiring Repairs.
2. Rear Low Level Audio Signal shorted--Test the Left or Right Rear Low Level Audio Signal circuit for a short to ground or to voltage. Refer to Circuit Testing and Wiring Repairs.
3. Center Channel Low Level Audio Signal shorted--Test the Center Channel Low Level Audio Signal for a short to ground or to voltage. Refer to Circuit Testing and Wiring Repairs.
4. Subwoofer Low Level Audio Signal shorted--Test the Subwoofer Low Level Audio Signal for a short to ground or to voltage. Refer to Circuit Testing and Wiring Repairs.
5. Defective Radio--Replace the Radio. Refer to Control Module References for replacement, setup and programming.
6. Defective amplifier--Replace the amplifier. Refer to Control Module References for replacement, setup and programming.