For 1990-2009 cars

### Important Preliminary Checks Before Starting

1. Review the Theft Deterrent System Description and Operation in order to familiarize yourself with the system functions. Refer to Content Theft Deterrent (CTD) Description and Operation and Immobilizer Description and Operation.
2. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:

• | There are no DTCs set.

• | The control modules can communicate via the serial data link.

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the keyless entry system. Refer to Checking Aftermarket Accessories.

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

### Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Content Theft Deterrent (CTD) Alarm Mode Inoperative

• | Horn Inoperative in Content Theft Deterrent (CTD) Alarm Mode

• | Lights Inoperative in Content Theft Deterrent (CTD) Alarm Mode

• | Security Indicator Inoperative

• | Inclination Sensor Inoperative

• | Intrusion Sensor Inoperative

• | Theft Deterrent Alarm Inoperative