Body Control Module: Description and Operation

Behind Center Of I/P Carrier:

GENERAL DESCRIPTION
The Central Control Module (CCM), located behind the center of the instrument panel, is the primary controller/processor for automatic functions of a number of electrical systems in the vehicle, including:

- Ambient Light Signal Processing
- Chimes (seat belt reminder, key in ignition reminder, etc.)
- Courtesy Lamp Control
- Delayed Accessory Bus (DAB) Control
Power Windows
Audio System
- Interior Lights Dimming Control
- Driver Information Center (DIC) Display
- Instrument Panel LCD Display
- Security System
- Rear Defog Control
- Oil Level/Life Monitoring
- Status Warnings ("Check Gauges" Indicator)
- System Component Fault Detection
- System Diagnostics Processor/Controller
- Trip Computer Processing
- Vehicle Speed Detection/Processing

and other functions.

The CCM also communicates with the Engine Control Module (ECM), Electronic Brake Control Module (EBCM), HVAC Programmer, and Radio Tuner Control Head, through the "Serial Data" Line. These controllers share data and sensor information so they can operate in "concert" to control related functions.

DIAGNOSTIC MODES
The CCM has diagnostic capabilities that can identify problems with input/output devices and circuits, and can access diagnostic information from the other controllers through the serial data line. The CCM uses the speedometer, odometer, and trip monitor, located on the instrument cluster, to display diagnostic information. The speedometer is used to display Diagnostic Trouble Codes (DTC). The odometer displays data values, and the tripmeter indicates the system being tested (module) and which test is being performed. Once the diagnostic mode is entered, the different display modes and tests are accessed by using the buttons on the Driver Information Center (DIC).

For more information, and procedures on using the CCM diagnostic mode to display codes and data through the instrument cluster, refer to TESTING AND INSPECTION.