Self-Diagnostic System: Description: Notes
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PCM is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, PCM will store a Diagnostic Trouble Code (DTC) and, in most cases, illuminate the Malfunction Indicator Light (MIL) located on instrument cluster. OBD-II requires that PCM illuminate MIL when a malfunction is detected that affects vehicle emissions. Malfunctions are recorded as hard failures or as intermittent failures.