Self-Diagnostic System: Notes

ECM or PCM is equipped with a self-diagnostic system which detects system failures or abnormalities. When malfunctioning occurs, Malfunction Indicator Light (MIL) in instrument panel is turned on.

By analyzing various input signals, ECM or PCM detects system malfunctions related to various operating parameter sensors. ECM or PCM stores diagnostic trouble codes associated with the detected failure until the diagnostic system is cleared.