Engine Diagnosis General Description

The engine and emission control systems in this vehicle are controlled by ECM. ECM has an On-Board Diagnostic (OBD) 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 of the outline of ON-BOARD DIAGNOSTIC (OBD) SYSTEM DESCRIPTION:J24B  and each item in PRECAUTIONS FOR DIAGNOSING TROUBLE:J24B  and execute diagnosis according to ENGINE AND EMISSION CONTROL SYSTEM CHECK:J24B .

There is a close relationship between the emission system, engine mechanical, engine cooling system, ignition system, exhaust system, etc. in their structure and operation. In case of an engine trouble, even when the malfunction indicator lamp (MIL) doesn't turn on, it should be diagnosed according to ENGINE AND EMISSION CONTROL SYSTEM CHECK:J24B .