Control Unit

An 88-pin control unit is used. See CONTROL UNIT LOCATION table. The control unit 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.

Control unit can operate engine in a "limp mode," allowing vehicle operation despite component failure. Control unit also has adaptive capabilities to compensate for component wear and other factors, such as minor air (vacuum) leaks. Once a fault is recognized, it is stored in control unit memory as a fault code. 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 the control unit by eliminating power to fuel injectors. The control unit assumes control of the following functions.

Acceleration Enrichment, Catalytic Converter Protection, Cold Start Control, Dynamic Coasting Shutoff, Fuel Injection Control, Fuel Tank Vent (Evaporation) Control, Idle Speed Control, Ignition Timing and Anti-Knock Function, Heated Oxygen (Sensor) Control, Relay Controls and Self-Diagnostics.

CONTROL UNIT LOCATION

Application	Location
All Models	Inside Box On Right Rear Corner Of Engine Compartment

NOTE: Components are grouped into 2 categories. The first category covers INPUT DEVICES, which control or produce voltage signals monitored by control unit. The second category covers OUTPUT SIGNALS , which are components controlled by the control unit.