Self-Diagnostic System: Introduction
ECM monitors engine and transaxle operation, and contains a self-diagnostic system which stores DTCs. A Malfunction Indicator Light (MIL), located on instrument panel, will illuminate if a system or component fails and sets a DTC. See Figure.
MIL illuminates for self-check with ignition on, engine off. If the MIL does not illuminate, check the MIL circuit and indicator bulb. See WIRING DIAGRAMS . Once engine is started, the MIL should go out. If the MIL remains illuminated, ECM has detected a malfunction or problem in transaxle electronic control system.
When a second-time malfunction or DTC is detected, the MIL will illuminate, provided ignition is turned off, and then back on after malfunction or DTC was first detected. This process is referred to as 2-trip detection logic and applies to most DTCs.
If malfunction does not reoccur within 3 consecutive trips, the MIL goes off, but DTC remains recorded in ECM memory. DTCs may only be retrieved using scan tool connected to 16-pin Data Link Connector 3 (DLC3) located under instrument panel, above pedal assembly. See Fig 1.
Scan tool can be used to clear DTCs and provide freeze-frame data. ECM records engine operating condition (fuel system, calculated load, coolant temperature, fuel trim (mixture), engine speed, vehicle speed, etc.). Recorded information is ONLY for the first recorded DTC, even if more than one DTC has been recorded. Freeze-frame data is only updated when all DTCs have been cleared, or a misfire or fuel-trim malfunction has occurred.