California Models

***UPDATED BY TSB #908902, dated 07-31-89

Digifant II Engine Management System:

The Digifant II engine management system combines control of the electronic port fuel injection and the TCI-h/knock ignition systems in a single control unit. All functions of the fuel, ignition, and idle speed stabilization systems are carefully controlled throughout the entire range of engine speed, engine load, and temperature conditions to produce maximum fuel efficiency and engine performance.
The air flow sensor, air intake sensor, coolant temperature sensor, Hall sender, throttle switches, oxygen sensor, and knock sensor provide the Digifant II control unit (ECU) with information concerning engine operating conditions. Based on the this information, the Digifant II control unit determines the appropriate output signals for injector pulse width, ignition timing point, and idle stabilization. The ECU also receives a signal from the A/C compressor clutch when activated. This additional input prevents a severe dip in idle speed resulting from the additional load before the idle stabilization system can compensate.

Fig. 3 On Board Diagnostic System Indicator Switch:

For California vehicles produced prior to January 1989, an on-board diagnostic system provides fault recognition and diagnosis for the engine management system. The Digifant II control unit utilizes an erasable permanent memory which stores and displays faults which may cause the vehicle to fail an exhaust emission inspection. Fault codes are displayed by an indicator/rocker switch on the instrument panel marked "CHECK".