Alarm Malfunction

Theft Deterrent Alarm Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

Note: Vehicles equipped with RPO UTP use a separate theft deterrent alarm instead of the vehicle horns during a theft deterrent alarm. This diagnostic procedure only applies to vehicles equipped with RPO UTP.

The body control module (BCM) controls the theft deterrent alarm by grounding the Content Theft PCB relay coil control circuit. When the BCM enters the content theft deterrent alarm mode, the Content Theft PCB relay coil control circuit is grounded. The Content Theft PCB relay will then provide voltage to the theft deterrent alarm control circuit, sounding the theft deterrent alarm.

Reference Information
Schematic Reference

Horn Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Horns System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the X50A underhood fuse block.
2. Connect a test lamp between the control circuit terminal 6 and B+.
3. Completely lower the driver door window and close all vehicle doors. Arm the content theft deterrent system by locking the door with the keyless entry transmitter. Wait 30 seconds.
4. Without disarming the system, reach in through the open driver window and open the driver door. The test lamp should turn ON and OFF.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

5. Ignition OFF, connect the X2 harness connector at the X50A underhood fuse block. Disconnect the harness connector at the P4 security siren.
6. Test for less than 1 ohm between the ground circuit terminal B and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect a test lamp between the control circuit terminal A and ground.
8. Completely lower the driver door window and close all vehicle doors. Arm the content theft deterrent system by locking the door with the keyless entry transmitter. Wait 30 seconds.
9. Without disarming the system, reach in through the open driver window and open the driver door. The test lamp should turn ON and OFF.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the X50A underhood fuse block.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the X50A underhood fuse block.

10. If all circuits test normal, test or replace the P4 security siren.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Accessory Wiring Junction Block Retainer Replacement (Removal and Replacement)
* Control Module References (Programming and Relearning)for BCM replacement, setup and programming