Body Function Controller (BFC)
The theft deterrent system's logic is contained within the Body Function
Controller (BFC). The BFC reads the Passlock® cylinder data from the Passlock®
lock cylinder within a certain timing window. If the Passlock® cylinder
data is correct and within the timed window, the BFC completes the following
functions:
| • | Transmits the coded password to the Powertrain Control Module
(PCM) |
The BFC may enter a theft mode in one of the two following ways:
| • | Bad Passlock® cylinder data |
If the Passlock® cylinder data is not read within the timed window,
the vehicle theft deterrent enters a short tamper mode during which the following
results occur:
| • | The PCM will not allow the car to operate for four seconds. |
| • | The BFC will send a SPI serial data message to the instrument
cluster. |
| • | The THEFT SYSTEM indicator will flash. |
After three consecutive failed timings, the Vehicle Theft Deterrent
(VTD) enters a long tamper mode. In this mode, the following actions occur:
| • | The BFC sends a SPI serial data message to the instrument cluster. |
| • | The THEFT SYSTEM indicator flashes. |
| • | The fuel injectors are disabled for approximately 10 minutes. |
Important: The vehicle may start before any tamper mode. However, the car will
quickly stall. If the BFC receives the wrong Passlock® data, the VTD immediately
enters the long tamper mode. The vehicle's fuel injectors will be locked-out
for 10 minutes.
The THEFT SYSTEM indicator flashes when the VTD is in any tamper mode.
The BFC continually verifies the operation of the VTD during the operation
of the vehicle. If the THEFT SYSTEM indicator lights continuously during
vehicle operation, refer to
Content Theft Deterrent (CTD) System Check
.
The BFC performs the following functions:
| • | A/C cooling fan control |
| • | Exterior and interior lighting control |
| • | Daytime Running Lights (DRL) |
| • | Automatic lighting control |
| • | Instrument cluster indicator control |
| • | Temperature gauge control |
For more information, refer to
Body Control System Operation
in Body Control Systems.
Class 2 Data Line
Class 2 data is a higher speed data transmission. In order to control
the serial data line traffic, Class 2 uses the peer to peer method along with
message arbitration in order to manage the data line traffic. The following
control modules are on the Class 2 data line:
| • | The Body Function Controller (BFC) |
| • | The Electronic Brake Control Module (EBCM) |
| • | The Powertrain Control Module (PCM) |
Serial Peripheral Interface (SPI) Data Line
The Serial Peripheral Interface (SPI) is a three wire interface connecting
the BFC to the instrument cluster. This arrangement allows for the BFC and
the instrument cluster to exchange information. The interface is a synchronous
serial data link where the BFC is the master and the instrument cluster is
the slave. The modules on the different serial data links need to communicate
with each other. The BFC acts as an interpreter, or master, for data communication
between the Class 2 and the SPI data lines.
Driver Warning System
The BFC is responsible for completing the following tasks:
- Interpreting all of the driver warnings sent by the control modules
on the Class 2 serial data line
- Sending that information on to the instrument cluster in the form
of a SPI serial data bus message
The following list of messages are sent by the BFC to the instrument
cluster:
| • | Temperature Gauge Position |
