Computers and Control Systems: Description and Operation

The heart of the EEC system is a microcomputer that processes input data from sensors and produces output control signals to the fuel injectors, regulating precise fuel discharge through the injector nozzles. The microcomputer circuit also produces output signals that adjust ignition spark timing to provide a best balance between driveability and fuel economy. The EEC system also controls the 4EAT transmission.
The system has built in diagnostic capabilities that when the ECA detects a system fault will store a trouble code in system memory. The code can be recalled from system memory to be used as a diagnostic aid.