CCD Bus

OPERATION
Various modules exchange information through a communications port called the CCD bus. The PCM transmits the Malfunction Indicator (Check Engine) Lamp On/Off signal and engine rpm on the CCD Bus. The PCM receives the air conditioning select input, transaxle gear position input and speed control engage inputs over the CCD Bus. The PCM also receives the air conditioning evaporator temperature signal from the CCD Bus.

The following components access or send information on the CCD Bus:
- Instrument panel
- Body Control Module
- Air Bag System Diagnostic Module
- Full ATC Display Head
- ABS Module
- Transmission Control Module
- Powertrain Control Module
- Overhead Travel Module

CIRCUIT OPERATION
The CCD Bus is used to allow the Powertrain Control Module (PCM) and other modules to communicate with each other and the universal data link connector.

Circuit D1 is used for CCD (+) and connects to cavity 59 of the PCM connector. Circuit D2 is used for CCD (-) and connects to cavity 60 of the PCM connector.

The CCD Bus is used to supply all of the communications between the Body Control Module (BCM) and the instrument cluster. The bus wires are a twisted pair. There are two different circuits used for the bus.

The positive side of the bus wire is accomplished on the D1 circuit, and the negative is on the D2 circuit.

The CCD Bus and the universal data link connector are used for access to the diagnostic capabilities of the radio. Circuits D1 and D2 are used.

The D1 circuit is used for CCD (+) and circuit D2 is used for CCD (-).