Data Link Connector (DLC)
The data link connector (DLC) terminal 2 contains the
class 2 serial data link.
The DLC also provides a power source for the scan tool as follows:
| • | Battery voltage at the DLC terminal 16. |
| • | Ground at terminals 4 and 5. |
Class 2 Serial Data Link
The class 2 serial data link allows the following modules to communicate
with each other:
| • | The body control module BCM |
| • | The electronic brake control module EBCM |
| • | The powertrain control module PCM |
| • | The Remote Control Door Lock Receiver RCDLR |
| • | The inflatable restraint sensing and diagnostic module SDM |
The class 2 serial data link allows a scan tool to communicate
with the above modules for diagnostic and testing purposes.
Serial Peripheral Interface
The serial peripheral interface, SPI bus is an exclusive 3 wire data
bus between the BCM and the IPC. The BCM and IPC are the only two modules
that communicate over the SPI bus. SPI circuit "A" is used to
transmit data from the BCM to the IPC, such as gage, speedometer and MIL control.
SPI circuit "B" functions as a communication link back to the
BCM from the IPC. The IPC sends information over SPI circuit "B"
to the BCM relative to tachometer and speedometer active status as well as
messages indicating that the BCM has sent corrupt or invalid data over the
SPI to the IPC. The third part of the SPI serial data link is the Clock circuit,
the SPI serial data clock circuit is generated in the BCM and transmitted
to the IPC so that both modules communications processes are synchronized.
All DTC's related to the SPI serial data circuit are handled by the BCM and
accessed through the Class 2 serial data bus. Refer to
DTC U2000-U2007
in
Body Control System for the diagnostic repair procedures for the SPI serial
data circuit.
