Daytona Shelby V6-181 3.0L SOHC (1991)
Body Controller: Description and Operation
CCD Bus
The Chrysler Collision Detection multiplex system (CCD bus) consists of a twisted pair of wires. These wires run from one module to another and from
each module to the body controller. They receive and deliver coded information between the modules and between each module and the body controller.
The information is coded to identify the message as well as the importance of the message. When there are multiple messages trying to access the CCD
bus at one time, the code is used to determine which one has higher priority and is allowed to access the bus first.
The two wires (D01) and D02) of the twisted pair that make up the CCD multiplex system are called "bus +" (bus plus) and "bus -" (bus minus). Both
wires have a measurable voltage level of roughly 2.5 volts. In order to maintain the 2.5 volts on each line and provide a means of transportation for the
coded messages, there is a "voltage divider network." This network consists of some modules with bias and some with termination. Bias is the part of the
voltage divider network that places both bus + and bus - at 2.5 volts. Termination is the circuitry required to complete the voltage divider network and
also provide some electromagnetic protection for the bus.
NOTE: Communication over the bus is essential to the proper operation of the vehicle's on-board diagnostic systems and the DRBII. Problems with the
operation of the bus or the DRBII must be corrected before proceeding with diagnostic testing. If there is a problem, refer to the Vehicle Communication
section for diagnosis and repair procedures.
