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.

### DTC Descriptors

DTC B291B 00: Content Theft Deterrent Sensor Malfunction
DTC B291B 39: Content Theft Deterrent Sensor Internal Malfunction
DTC B291B 42: Content Theft Deterrent Sensor Calibration Not Programmed

### Circuit/System Description

This diagnostic applies to internal microprocessor integrity conditions within the content theft sensor (intrusion/inclination sensor).

### Conditions for Running the DTC

• | The ignition is OFF.

• | The vehicle is in Park.

### Conditions for Setting the DTC

The body control module detects an internal failure within the content theft sensor.

### Action Taken When the DTC Sets

The intrusion and inclination output is disabled

### Conditions for Clearing the DTC

• | A current DTC is cleared when the conditions for setting the DTC are no longer present.

• | A history DTC will clear after 40 malfunction free ignition cycles.

### 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 Testing

1. Verify that DTC B291B is not set.

⇒ | If the DTC is set, program the B79 content theft deterrent sensor. If the DTC resets, replace the B79 content theft deterrent sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for body control module replacement, setup, and programming.