Self-Diagnostic System: Description

ECM constantly looks at information from various input devices to control systems that affect vehicle performance. ECM self-diagnostic capabilities allow for trouble shooting system through a Malfunction Indicator Light (MIL). MIL will illuminate to alert driver of a system malfunction. The type of failure (hard or intermittent) will affect how the MIL illuminates. The specific malfunction can be determined via a 2-digit code displayed by MIL. To retrieve codes, see appropriate TESTS W/CODES article.