Computers and Control Systems: Description and Operation

Fig. 2 Closed Loop Emission Control system schematic.:

ECM Connections Identification:

The Closed Loop Emission Control System, Fig. 2 is used on all California Trooper II models. The system is used to provide precise control of the air/fuel mixtures, allowing use of a dual bed 3-way catalytic converter and to control air flow in the AIR system. System components include an electronic Control Module (ECM), oxygen sensor, vacuum fuel control valve and duty solenoid, electronically controlled carburetor and other sensors and actuators. The three-way catalytic converter is also considered part of this system.

With the engine running and if a problem develops in the system the "CHECK ENGINE" lamp will come "on" and a trouble code will be stored in the ECM "Trouble Code Memory". The lamp will remain on with engine running as long as there is a problem. If the problem is intermittent, the "CHECK ENGINE" lamp will go out but the trouble code will be stored in the ECM trouble code memory.

With the ignition turned "ON" and the engine stopped, the "CHECK ENGINE" lamp should be "ON". This is a bulb check to indicate that the lamp is working.