Computers and Control Systems: Description and Operation

GENERAL DESCRIPTION
This vehicle is equipped with an engine and emission control system which are under control of Electronic Control Module (ECM).
The engine and emission control system in this vehicle are controlled by ECM. ECM has an On-Board Diagnostic system which detects a malfunction in this system and abnormality of those parts that influence the engine exhaust emission. When diagnosing engine troubles, be sure to have full understanding and execute diagnosis.
There is a close relationship between the engine mechanical, engine cooling system, ignition system, exhaust system, etc. and the engine and emission control system in their structure and operation. In case of an engine trouble, even when the malfunction indicator lamp (MIL, "SERVICE ENGINE SOON" lamp) doesn't turn ON, it should be diagnosed according to the flow chart.