Self-Diagnostic Systems

Engine Control Module (ECM) is equipped with self-diagnostic system. By analyzing various input signals, ECM detects system malfunctions related to various operating parameters. When malfunction occurs, ECM may inform the driver by turning on Malfunction Indicator Light (MIL) on the instrument panel.

NOTE: MIL may be referred to as CHECK ENGINE light.

Diagnostic Trouble Codes (DTC) may be set by malfunction of various engine sensors, switches or circuits. DTC is stored in ECM memory. When DTC is stored, MIL on instrument panel will come on. DTC can be retrieved for system diagnosis. For additional information on self-diagnostic system, see SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving and servicing of DTCs.