Daytona Shelby V6-181 3.0L SOHC (1991)
Body Controller: Description and Operation
Body Control Module
There is only one body controller available on the 1991 Daytona (G-body) or LeBaron (J-body).
The style of body controller on the vehicle depends on the options the vehicle is equipped with.
For a "premium" body controller, the vehicle is equipped with either an Electronic Instrument Cluster or EVIC (Electronic Vehicle Information Center).
For a "base" body controller, the vehicle would be equipped with a Mechanical Instrument Cluster and not an EVIC.
The body controller provides power or ground for a variety of systems. It uses a voltage drop to monitor these systems.
The body controller is the only module that has the capability of providing both bias and termination on the CCD bus system.
The body controller receives information from the engine node about brake fluid level, engine coolant level, and engine oil level.
Exterior lamps are monitored by the lamp outage module. If a problem occurs with a head lamp, tail lamp, or brake lamp, the lamp outage module senses
the discrepancy and reports the condition to the body controller.
The body controller is used to store odometer information displayed in the electronic instrument cluster (see the "Electronic Instrument Cluster"
description later in this section).
NOTE: When replacement of the body controller is required, contact your service center to obtain an exchange body controller.
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.
Compass/Temperature Module
The Compass/Temperature module is located in the overhead console. It displays to the driver the direction the vehicle is traveling and the current
outside temperature.
If the vehicle is equipped with an EVIC panel and a Compass/Temperature module, the Compass/Temperature module sends navigational information to
the EVIC panel via the CCD bus. The Engine Node module provides the Compass/Temperature module with the outside temperature.
When the Compass/Temperature module has been replaced it may be necessary to reset the calibration.
Electronic Vehicle Information Center (EVIC)
The Electronic Vehicle Information Center (EVIC) module is located in the dash (same location as the Traveler). It displays to the driver such
information as time, outside temperature, compass direction, and fuel economy.
The EVIC panel monitor receives messages from other modules on the CCD bus about the status of a variety of Systems and components (see TEST 3A
for a list of the messages). Any failure of a monitored system results in a warning message on the EVIC panel monitor.
Glossary of Terms/Acronyms
ADL - automatic door lock
PDC - Power Distribution Center
VTA - vehicle theft alarm
Mechanical Instrument Cluster (MIC)
