General Testing Description

The system self-test is divided into four specialized tests, Key-On/Engine-Off self-test, Engine Running self-test, Continuous self-test and the switch monitor test. The self-test is not a conclusive test by itself, 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 electronic engine control system by testing its memory integrity and processing capability, and verifies that various sensors and actuators are connected and operating properly.
Unlike the EEC-IV system, no sensors or switches are exercised during the self-test. Also, intermittent codes are not erased if the fault is removed after 40 vehicle starts and stops. Therefore, any intermittent codes will be stored in permanent memory until erased. Service codes for output devices are not kept in memory and will exist only during Key-On testing, all other codes (input devices) are kept in permanent memory and must be erased after servicing.