Important: Due to component variability, the vehicle theft deterrent (VTD) system
must have the learn procedure performed regardless, if the vehicle starts
on the first ignition cycle after a VTD repair.
All codes in the theft deterrent module must be cleared for a relearn.
The vehicle theft deterrent system is designed in order to prevent
vehicle theft by disabling the fuel injectors unless the lock cylinder is
correctly engaged by a mechanical key. The theft deterrent system uses the
following 4 components for theft prevention:
| • | The body control module (BCM) |
| • | The powertrain control module (PCM) |
When starting the engine, the PCM searches for a password from the BCM
through the Class 2 serial data circuit. If the password is not recognized
or not present, the PCM will disable the engine. Two modes of tamper detection
are provided:
| | The engine will start and stall
quickly. SECURITY telltale will flash on the instrument panel cluster (IPC)
and then stay ON steady. |
| • | Incorrect or disable password received (More than 3 invalid
passwords are received) |
| | The engine is disabled for at least 10 minutes
and the SECURITY telltale will illuminate solid on the IPC during the 10 minutes. |
After the vehicle has passed theft detection, the PCM will continue
normal operation.
Ignition Switch
The mechanical key and lock cylinder is located in the instrument panel
assembly. The electrical switching portion of the assembly is separate
from the key and lock cylinder. Both of the components are synchronized
and work in conjunction through the action of the actuator rod assembly.
Passlock™ Lock Cylinder
The Passlock™ lock cylinder is a locking cylinder that turns a
rotating magnet past a stationary hall effect sensor. This action creates
the Passlock™ cylinder data. The Passlock™ cylinder data
is sent to the body control module (BCM). The Passlock™ lock cylinder
is interfaced with the BCM via a 3-wire connection:
Powertrain Control Module (PCM)
The Powertrain Control Module (PCM) is located on the lower left side
of the instrument panel.
The PCM communicates with the body control module (BCM) via serial data
over the class 2 serial data bus, CKT 1807. When the BCM
determines a passed theft condition, the BCM sends a coded password to
the PCM. When the PCM receives the correct password, the PCM enables
the fuel injection system, allowing the vehicle to operate correctly.
The PCM may allow the car to start and quickly stall during a failed
theft condition.
The following conditions may cause the PCM to enter a tamper mode:
If the BCM does not receive a password within a preset time window,
the BCM will enter a short tamper mode. During this mode, the PCM will not
allow the car to operate for 4 seconds.
If the password is incorrect, the PCM will enter the long tamper mode.
In the long tamper mode, the following actions will occur:
| • | The THEFT SYSTEM indicator will flash. |
| • | The fuel injectors will be shut off for approximately 10 minutes. |
Although the vehicle may start, the engine will quickly stall due to
a fuel cut-off.
In the event of an open in the serial data communication between the
BCM and the PCM, the following actions occur:
| • | The PCM will become fail-enabled if the car has already passed
theft for that ignition cycle (i.e. the engine is running). |
| • | The PCM may set the diagnostic trouble codes (DTC). |
| • | The THEFT SYSTEM indicator will light continuously. |
| • | The PCM will become fail-enabled for future ignition cycles. |
If a failure occurs in serial data before the ignition cycle, while
the PCM is not fail-enabled, the PCM will never receive a valid password
in order to enable the continued use of the fuel injectors.
