Computers and Control Systems: Description and Operation

ECM Inputs/Outputs:

SYSTEM DESCRIPTION:

This vehicle uses several electronic components which form an electronic computer network, designed to control various engine and body sub-systems. The heart of the computer network is the Body Computer Module (BCM). The BCM has an internal microprocessor which is the center for communication with all the other components, and controls the on-board diagnostics of the vehicle. All system sensors and switches are monitored by the BCM or one of the four other major components that complete the computer system network. The other four components are the Climate Control Driver Information Center (CCDIC), Electronic Control Module (ECM), HVAC Programmer, and the Instrument Panel Cluster (IPC).

The CCDIC is used by the driver to control the air conditioner and heating system, also used to retrieve diagnostic information (i.e. trouble codes, sensor parameters, etc.), or override certain output components. The ECM controls the fuel and ignition systems to obtain good performance and low exhaust emissions. The IPC is used to display information to the driver such as vehicle speed, engine rpm, and fuel level. The HVAC Programmer receives information from the CCDIC and carries out the commands necessary to obtain the correct interior temperature.

All components in the system are always in continuous communication with each other to provide accurate control over the many sub-systems involved. When one or more of these sub-system circuits exceeds pre-programmed limits a malfunction is indicated by a service engine soon warning lamp, and a backup function may be activated until the malfunction is corrected.