For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

To deter theft, the radio learns and stores the vehicle VIN. If the radio is removed from the vehicle and installed into another vehicle, the radio performs a VIN check. If the VIN stored in the radio and the VIN being reported over serial data do not match or no VIN is received, the radio will go into a theft lock state and be inoperative. The radio will also display LOC, LOCKED, or CODE.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Radio/Audio System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Ignition ON, perform radio setup procedure. Refer to Radio Programming and Setup. Verify the radio operates normally and no messages are displyed on the radio.

⇒ | If the message continues to display on the radio, replace the radio.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for radio replacement, programming, and setup