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 security indicator acts as a status indicator for the theft deterrent system when the ignition is OFF and a fault indicator for the Immobilizer system with the ignition ON. When the body control module (BCM) requires the security indicator to be illuminated, the telltale control circuit to the instrument panel cluster (IPC) is grounded. The security indicator will also illuminate during IPC display test.

### Diagnostic Aids

Ignition ON, verify the security indicator illuminates when performing the scan tool IPC Display Test.

⇒ | If the security indicator does not illuminate during the display test, replace the IPC.

### Reference Information

#### Schematic Reference

Theft Deterrent System Schematics

#### Connector End View Reference

Data Communication 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Circuit/System Testing

#### Security Indicator Inoperative

Test for an open/high resistance in the security indicator control circuit.

⇒ | If a condition is found make the appropriate repair.

⇒ | If the circuit tests normal, then replace the BCM.

#### Security Indicator Always ON or Flashing

1. Disconnect the BCM connector containing the security indicator control circuit. Back out the terminal for the security indicator control circuit and reconnect to BCM. Ignition ON, engine OFF. After the IPC display test has completed, the security indicator should remain OFF.

⇒ | If the security indicator remains OFF, replace the BCM. Refer to Repair Instructions.

2. Test for a short to ground in the security indicator control circuit.

⇒ | If a condition is found make the appropriate repair.

⇒ | If the circuit tests normal, then replace the IPC. Refer to Repair Instructions.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM and IPC replacement, programming and setup