The Universal Theft Deterrent (UTD) system is a subsystem of the Body Control Module (BCM). The BCM provides all logic necessary to operate the UTD system. The BCM also sends and receives information from other systems to perform UTD functions, therefore, it is important to become familiar with general operation of the BCM and how the BCM sends and receives information from other systems to execute UTD functions. Use a scan tool in order to diagnose the UTD system when referred to in diagnostic procedures. In addition to displaying DTCs, the scan tool can be used to display BCM input status and the data values used. The scan tool can also be used to instruct the BCM to command many UTD subsystems ON or OFF. Any of these features can be selected using the scan tool. Become very familiar with the BCM capabilities and diagnostic features. These self-diagnostic features are referenced in the DTC tables and are very useful in diagnosing non-DTC setting malfunctions as well. Most system malfunctions are traceable to faulty wiring and connectors, and occasionally components. Using a scan tool to display data while moving wiring or connector can help diagnose an intermittent malfunction. For the BCM to provide UTD functions, the BCM relies on other systems to provide information that is not a direct input to the BCM. This information can be received either by a direct circuit to the BCM, or by a specific message to the BCM on the serial data line. The following table describes input and output information the BCM uses to perform UTD functions and how the BCM receives this information:
UTD Input | Signal Source | Signal Path to BCM |
|---|---|---|
Courtesy light switch status | Courtesy light switch, IPC | Serial data line |
Door ajar switch | Door ajar switch, BCM | CKT 745 and CKT 746 |
Door lock cylinder | Door lock switch, LDCM, RDCM | Serial data line |
Power door lock switch | Power door lock switch, LDCM, RDCM | Serial data line |
Hatch ajar switch | Hatch ajar switch, BCM | CKT 744 |
Hood ajar switch (export) | Hood ajar switch, BCM | CKT 109 |
Ignition switch position | Ignition switch, BCM | CKT 1039, CKT 243, CKT 141 |
Key in ignition status | Ignition switch, BCM | CKT 60 |
Parking light status | Parking light switch, IPC | Serial data line |
PASS-Key® detection | Igniton switch, BCM | CKT 1073 and CKT1074 |
Fuel enable password | PCM, BCM | Serial data line |
Remote transmitter (keyless enrtry) | RFA | Serial data line |
To test operation of the UTD system, an illegal entry can be simulated. Perform the UTD test as follows:
- Ensure hatch is closed and latched.
- Sit in driver's seat with doors closed.
- The ON the ignition switch.
- Open a window with power window switch.
- Turn OFF the park/headlamps.
- Turn OFF the ignition and remove the ignition key.
- Open door to exit vehicle; SECURITY lamp should be flashing.
- Lock doors using power lock switch; SECURITY lamp should be ON continuously (not flashing).
- Exit vehicle and close door; SECURITY lamp should go out in 2-3 seconds.
- Reach through open window and unlock doors using either manual locks or power unlock switch.
- Open door; alarm should activate.
- Disarm UTD alarm mode by either inserting oval-head key in door lock cylinder and turning as if unlocking door, insert square-head key in ignition switch with a vaid PASS-Key®, or press the unlock button on the remote door lock transmittor.
If the UTD system does not operate as described above, check the operation of the following items using a scan tool:
| • | Door ajar switches (BCM) |
| • | Door key switches (door control modules) |
| • | Remote door lock transmitter (RFA |
| • | Power door lock/unlock switches (door control modules) |
If the above items check OK, cycle the horn and/or lights (fog, backup, turn signals) output through the BCM output control functions, or the SECURITY indicator through the IPC output control functions using a scan tool. These systems must be diagnosed first before diagnosing the UTD system.
