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

The content theft deterrent (CTD) system is a software based system in which the rear electrical cneter (REC) actively monitors certain inputs to determine if unauthorized vehicle access is being attempted. Based on inputs such as the door ajar switches, the trunk ajar switch, and the drivers door key cylinder switch, the REC determines whether a CTD alarm is warranted. If unauthorized access is being detected, the REC will pulse the vehicle horn and flash the exterior lights as a means of theft deterrent.

### Reference Information

#### Schematic Reference

Theft Deterrent System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Content Theft Deterrent (CTD) 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

1. Individually open and close each vehicle door while observing the door ajar indicator/message. The indicator/message should accurately transition between the door ajar and door closed state when each door is opened and closed.

⇒ | If the door ajar indicator/message does not properly transition when each door is opened and closed, refer to Door Ajar Indicator Malfunction .

2. Insert the vehicle key into the driver door key cylinder and rotate the cylinder between the idle and unlock positions. Verify the scan tool LF Key Cylinder Lock Switch parameter cycles between Idle and Unlock.

⇒ | If the scan tool parameter does not cycle between the specified parameters, refer to Content Theft Deterrent (CTD) Does Not Disarm with Key Lock .

3. Completely lower the driver door window and close all vehicle doors.
4. Ignition OFF, arm the CTD system using the keyless entry system by pressing the keyless entry transmitter LOCK button twice.
5. With the door open, verify the vehicle horn is pulsing and the exterior lamps are flashing.

⇒ | If the horn is not pulsing, refer to Horns Malfunction .