System Description

The Computerized Engine Control System is built around the electronic Multi-Point Injection (MPI) Control Unit. The Engine Controller constantly monitors signals from various sensors and responds by actuating output devices to maintain optimum performance and fuel economy.

SENSORS/INPUTS

^ Power Supply (Ignition Switch Coupled)
^ Power Supply (Battery Backup)
^ Air Flow Sensor
^ Barometric Pressure Sensor
^ Intake Air Temperature Sensor
^ Engine Coolant Temperature Sensor
^ Throttle Position Sensor
^ Idle Position Switch
^ Camshaft Position (TDC) Sensor
^ Crankshaft Position Sensor
^ Oxygen Sensor
^ Vehicle Speed Sensor
^ A/C ON-OFF Switch
^ Ignition Switch ST terminal (start signal)
^ Power Steering Oil Pressure Switch
^ Park/Neutral Safety Switch (A/T)
^ Exhaust Gas Temperature Sensor (California Models Only)


ACTUATORS/OUTPUTS

^ Fuel Injector Pulse Width
^ Idle Air Control (IAC) Motor
^ Ignition Timing Power Transistor
^ Air-Conditioner Power Relay
^ Fuel Pump Control Relay
^ Evaporative Emission Purge Control Solenoid Valve
^ EGR Control Solenoid Valve (California Models Only)
^ Self-Diagnosis Output
^ Malfunction Indicator light

Check Engine / Malfunction Indicator Lamp:

MALFUNCTION INDICATOR LIGHT

If a component or system malfunction is detected, the Engine Controller will illuminate the "MALFUNCTION INDICATOR LIGHT" and record the corresponding trouble code(s) in memory. However, when the engine control unit judges that the component or system has returned to normal, the MPI control unit will turn off the Malfunction Indicator Light. If the ignition switch is turned OFF and then ON again, the Engine Controller will not illuminate the Malfunction Indicator Light until the irregularity is detected again.
Under normal conditions, the Malfunction Indicator Light will be lit for 2.5 seconds immediately after the engine is started. This is to indicate that the light is not burned out and is operating normally.

NOTE: When the Ignition Timing Adjustment Terminal is shorted to ground during ignition timing inspection/adjustment procedures, the Control Unit will store a Fault Code 36 in memory and illuminate the Malfunction Indicator Light.