Single Module Engine Controller (SMEC)

The SMEC contains the operating software and performs calculations and adjustments necessary for engine operation. The SMEC is located at the front of the left fender panel in the engine compartment. The SMEC is a microprocessor-based digital computer, with 60-pin and 14-pin connectors. The SMEC receives input signals from various switches, sensors and other components. Using these signals, the microprocessor computes fuel injector pulse width, spark advance, ignition coil dwell, automatic idle speed actuation, canister purge cycle, cooling fan operation and alternator output.

The SMEC also contains a diagnostic circuit to test input and output circuits. The diagnostic circuit will store information about any malfunctions as they occur for read-out prior to service. The Chrysler Motors Diagnostic Read-Out Box (C-4805) or the flashing "CHECK ENGINE" light may be used in diagnosing and displaying trouble codes. The "CHECK ENGINE" light is limited in its diagnostic capabilities.