Electronic Control Unit (Ecu): Notes

An 88-pin ECU is used. See Figure. ECU uses the following input signals to determine optimum fuel injection and ignition timing: intake airflow, intake air temperature, throttle position, coolant temperature, engine speed, vehicle speed, crankshaft position, knock sensors and exhaust gas oxygen content.

ECU can operate engine in a limp mode, allowing vehicle operation despite component failure. ECU also has adaptive capabilities to compensate for component wear and other factors, such as minor vacuum leaks. Once a fault is recognized, it is stored in ECU memory as a Diagnostic Trouble Code (DTC). The system automatically substitutes a fixed replacement value for the incorrect value caused by a defective component or circuit.

An air/fuel ratio of 14.7:1 is maintained under most driving conditions. Maximum engine RPM is limited by ECU by eliminating power to fuel injectors. The ECU assumes control of following functions.