General Testing Description

The self-test is divided into three tests: Key-ON/Engine OFF, engine running and Continuous testing. The self-test is not a conclusive test, but is used as part of the functional Quick Test diagnostic procedure. The processor stores the self-test program in its permanent memory. When activated, it checks the EEC-IV system by testing its memory and processing capability, then verifies that the various sensors and actuators are connected and operating properly. The Key-ON/Engine OFF and Engine Running tests are functional tests which only detect faults present at the time of the self-test. Continuous testing is an ongoing test that stores fault information (memory codes) for retrieval at a later time (during the self-test). Before performing the self-test, the engine should be at normal operating temperature for the self-test to give accurate information. Some models equipped with 4-140 high swirl combustion engine and automatic transmission, have a vacuum restricter (VREST) located between the thermactor air control valve (ACV) and the vacuum retard valve (VRDV). The cap must be removed from the vacuum restricter during the self-test procedure. After the self-test procedure has been completed, install cap onto vacuum restricter.